1 //===--- MicrosoftCXXABI.cpp - Emit LLVM Code from ASTs for a Module ------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This provides C++ code generation targeting the Microsoft Visual C++ ABI.
11 // The class in this file generates structures that follow the Microsoft
12 // Visual C++ ABI, which is actually not very well documented at all outside
15 //===----------------------------------------------------------------------===//
18 #include "CGVTables.h"
19 #include "CodeGenModule.h"
20 #include "CodeGenTypes.h"
21 #include "TargetInfo.h"
22 #include "clang/AST/Decl.h"
23 #include "clang/AST/DeclCXX.h"
24 #include "clang/AST/StmtCXX.h"
25 #include "clang/AST/VTableBuilder.h"
26 #include "llvm/ADT/StringExtras.h"
27 #include "llvm/ADT/StringSet.h"
28 #include "llvm/IR/CallSite.h"
29 #include "llvm/IR/Intrinsics.h"
31 using namespace clang;
32 using namespace CodeGen;
36 /// Holds all the vbtable globals for a given class.
37 struct VBTableGlobals {
38 const VPtrInfoVector *VBTables;
39 SmallVector<llvm::GlobalVariable *, 2> Globals;
42 class MicrosoftCXXABI : public CGCXXABI {
44 MicrosoftCXXABI(CodeGenModule &CGM)
45 : CGCXXABI(CGM), BaseClassDescriptorType(nullptr),
46 ClassHierarchyDescriptorType(nullptr),
47 CompleteObjectLocatorType(nullptr), CatchableTypeType(nullptr),
48 ThrowInfoType(nullptr), CatchHandlerTypeType(nullptr) {}
50 bool HasThisReturn(GlobalDecl GD) const override;
51 bool hasMostDerivedReturn(GlobalDecl GD) const override;
53 bool classifyReturnType(CGFunctionInfo &FI) const override;
55 RecordArgABI getRecordArgABI(const CXXRecordDecl *RD) const override;
57 bool isSRetParameterAfterThis() const override { return true; }
59 size_t getSrcArgforCopyCtor(const CXXConstructorDecl *CD,
60 FunctionArgList &Args) const override {
61 assert(Args.size() >= 2 &&
62 "expected the arglist to have at least two args!");
63 // The 'most_derived' parameter goes second if the ctor is variadic and
65 if (CD->getParent()->getNumVBases() > 0 &&
66 CD->getType()->castAs<FunctionProtoType>()->isVariadic())
71 StringRef GetPureVirtualCallName() override { return "_purecall"; }
72 StringRef GetDeletedVirtualCallName() override { return "_purecall"; }
74 void emitVirtualObjectDelete(CodeGenFunction &CGF, const CXXDeleteExpr *DE,
75 llvm::Value *Ptr, QualType ElementType,
76 const CXXDestructorDecl *Dtor) override;
78 void emitRethrow(CodeGenFunction &CGF, bool isNoReturn) override;
79 void emitThrow(CodeGenFunction &CGF, const CXXThrowExpr *E) override;
81 void emitBeginCatch(CodeGenFunction &CGF, const CXXCatchStmt *C) override;
83 llvm::GlobalVariable *getMSCompleteObjectLocator(const CXXRecordDecl *RD,
84 const VPtrInfo *Info);
86 llvm::Constant *getAddrOfRTTIDescriptor(QualType Ty) override;
88 getAddrOfCXXCatchHandlerType(QualType Ty, QualType CatchHandlerType) override;
90 bool shouldTypeidBeNullChecked(bool IsDeref, QualType SrcRecordTy) override;
91 void EmitBadTypeidCall(CodeGenFunction &CGF) override;
92 llvm::Value *EmitTypeid(CodeGenFunction &CGF, QualType SrcRecordTy,
94 llvm::Type *StdTypeInfoPtrTy) override;
96 bool shouldDynamicCastCallBeNullChecked(bool SrcIsPtr,
97 QualType SrcRecordTy) override;
99 llvm::Value *EmitDynamicCastCall(CodeGenFunction &CGF, llvm::Value *Value,
100 QualType SrcRecordTy, QualType DestTy,
101 QualType DestRecordTy,
102 llvm::BasicBlock *CastEnd) override;
104 llvm::Value *EmitDynamicCastToVoid(CodeGenFunction &CGF, llvm::Value *Value,
105 QualType SrcRecordTy,
106 QualType DestTy) override;
108 bool EmitBadCastCall(CodeGenFunction &CGF) override;
111 GetVirtualBaseClassOffset(CodeGenFunction &CGF, llvm::Value *This,
112 const CXXRecordDecl *ClassDecl,
113 const CXXRecordDecl *BaseClassDecl) override;
116 EmitCtorCompleteObjectHandler(CodeGenFunction &CGF,
117 const CXXRecordDecl *RD) override;
119 void initializeHiddenVirtualInheritanceMembers(CodeGenFunction &CGF,
120 const CXXRecordDecl *RD) override;
122 void EmitCXXConstructors(const CXXConstructorDecl *D) override;
124 // Background on MSVC destructors
125 // ==============================
127 // Both Itanium and MSVC ABIs have destructor variants. The variant names
128 // roughly correspond in the following way:
130 // Base -> no name, just ~Class
131 // Complete -> vbase destructor
132 // Deleting -> scalar deleting destructor
133 // vector deleting destructor
135 // The base and complete destructors are the same as in Itanium, although the
136 // complete destructor does not accept a VTT parameter when there are virtual
137 // bases. A separate mechanism involving vtordisps is used to ensure that
138 // virtual methods of destroyed subobjects are not called.
140 // The deleting destructors accept an i32 bitfield as a second parameter. Bit
141 // 1 indicates if the memory should be deleted. Bit 2 indicates if the this
142 // pointer points to an array. The scalar deleting destructor assumes that
143 // bit 2 is zero, and therefore does not contain a loop.
145 // For virtual destructors, only one entry is reserved in the vftable, and it
146 // always points to the vector deleting destructor. The vector deleting
147 // destructor is the most general, so it can be used to destroy objects in
148 // place, delete single heap objects, or delete arrays.
150 // A TU defining a non-inline destructor is only guaranteed to emit a base
151 // destructor, and all of the other variants are emitted on an as-needed basis
152 // in COMDATs. Because a non-base destructor can be emitted in a TU that
153 // lacks a definition for the destructor, non-base destructors must always
154 // delegate to or alias the base destructor.
156 void buildStructorSignature(const CXXMethodDecl *MD, StructorType T,
157 SmallVectorImpl<CanQualType> &ArgTys) override;
159 /// Non-base dtors should be emitted as delegating thunks in this ABI.
160 bool useThunkForDtorVariant(const CXXDestructorDecl *Dtor,
161 CXXDtorType DT) const override {
162 return DT != Dtor_Base;
165 void EmitCXXDestructors(const CXXDestructorDecl *D) override;
167 const CXXRecordDecl *
168 getThisArgumentTypeForMethod(const CXXMethodDecl *MD) override {
169 MD = MD->getCanonicalDecl();
170 if (MD->isVirtual() && !isa<CXXDestructorDecl>(MD)) {
171 MicrosoftVTableContext::MethodVFTableLocation ML =
172 CGM.getMicrosoftVTableContext().getMethodVFTableLocation(MD);
173 // The vbases might be ordered differently in the final overrider object
174 // and the complete object, so the "this" argument may sometimes point to
175 // memory that has no particular type (e.g. past the complete object).
176 // In this case, we just use a generic pointer type.
177 // FIXME: might want to have a more precise type in the non-virtual
178 // multiple inheritance case.
179 if (ML.VBase || !ML.VFPtrOffset.isZero())
182 return MD->getParent();
186 adjustThisArgumentForVirtualFunctionCall(CodeGenFunction &CGF, GlobalDecl GD,
188 bool VirtualCall) override;
190 void addImplicitStructorParams(CodeGenFunction &CGF, QualType &ResTy,
191 FunctionArgList &Params) override;
193 llvm::Value *adjustThisParameterInVirtualFunctionPrologue(
194 CodeGenFunction &CGF, GlobalDecl GD, llvm::Value *This) override;
196 void EmitInstanceFunctionProlog(CodeGenFunction &CGF) override;
198 unsigned addImplicitConstructorArgs(CodeGenFunction &CGF,
199 const CXXConstructorDecl *D,
200 CXXCtorType Type, bool ForVirtualBase,
202 CallArgList &Args) override;
204 void EmitDestructorCall(CodeGenFunction &CGF, const CXXDestructorDecl *DD,
205 CXXDtorType Type, bool ForVirtualBase,
206 bool Delegating, llvm::Value *This) override;
208 void emitVTableDefinitions(CodeGenVTables &CGVT,
209 const CXXRecordDecl *RD) override;
211 llvm::Value *getVTableAddressPointInStructor(
212 CodeGenFunction &CGF, const CXXRecordDecl *VTableClass,
213 BaseSubobject Base, const CXXRecordDecl *NearestVBase,
214 bool &NeedsVirtualOffset) override;
217 getVTableAddressPointForConstExpr(BaseSubobject Base,
218 const CXXRecordDecl *VTableClass) override;
220 llvm::GlobalVariable *getAddrOfVTable(const CXXRecordDecl *RD,
221 CharUnits VPtrOffset) override;
223 llvm::Value *getVirtualFunctionPointer(CodeGenFunction &CGF, GlobalDecl GD,
225 llvm::Type *Ty) override;
227 llvm::Value *EmitVirtualDestructorCall(CodeGenFunction &CGF,
228 const CXXDestructorDecl *Dtor,
229 CXXDtorType DtorType,
231 const CXXMemberCallExpr *CE) override;
233 void adjustCallArgsForDestructorThunk(CodeGenFunction &CGF, GlobalDecl GD,
234 CallArgList &CallArgs) override {
235 assert(GD.getDtorType() == Dtor_Deleting &&
236 "Only deleting destructor thunks are available in this ABI");
237 CallArgs.add(RValue::get(getStructorImplicitParamValue(CGF)),
241 void emitVirtualInheritanceTables(const CXXRecordDecl *RD) override;
243 llvm::GlobalVariable *
244 getAddrOfVBTable(const VPtrInfo &VBT, const CXXRecordDecl *RD,
245 llvm::GlobalVariable::LinkageTypes Linkage);
247 void emitVBTableDefinition(const VPtrInfo &VBT, const CXXRecordDecl *RD,
248 llvm::GlobalVariable *GV) const;
250 void setThunkLinkage(llvm::Function *Thunk, bool ForVTable,
251 GlobalDecl GD, bool ReturnAdjustment) override {
252 // Never dllimport/dllexport thunks.
253 Thunk->setDLLStorageClass(llvm::GlobalValue::DefaultStorageClass);
256 getContext().GetGVALinkageForFunction(cast<FunctionDecl>(GD.getDecl()));
258 if (Linkage == GVA_Internal)
259 Thunk->setLinkage(llvm::GlobalValue::InternalLinkage);
260 else if (ReturnAdjustment)
261 Thunk->setLinkage(llvm::GlobalValue::WeakODRLinkage);
263 Thunk->setLinkage(llvm::GlobalValue::LinkOnceODRLinkage);
266 llvm::Value *performThisAdjustment(CodeGenFunction &CGF, llvm::Value *This,
267 const ThisAdjustment &TA) override;
269 llvm::Value *performReturnAdjustment(CodeGenFunction &CGF, llvm::Value *Ret,
270 const ReturnAdjustment &RA) override;
272 void EmitThreadLocalInitFuncs(
274 ArrayRef<std::pair<const VarDecl *, llvm::GlobalVariable *>>
276 ArrayRef<llvm::Function *> CXXThreadLocalInits,
277 ArrayRef<llvm::GlobalVariable *> CXXThreadLocalInitVars) override;
279 bool usesThreadWrapperFunction() const override { return false; }
280 LValue EmitThreadLocalVarDeclLValue(CodeGenFunction &CGF, const VarDecl *VD,
281 QualType LValType) override;
283 void EmitGuardedInit(CodeGenFunction &CGF, const VarDecl &D,
284 llvm::GlobalVariable *DeclPtr,
285 bool PerformInit) override;
286 void registerGlobalDtor(CodeGenFunction &CGF, const VarDecl &D,
287 llvm::Constant *Dtor, llvm::Constant *Addr) override;
289 // ==== Notes on array cookies =========
291 // MSVC seems to only use cookies when the class has a destructor; a
292 // two-argument usual array deallocation function isn't sufficient.
294 // For example, this code prints "100" and "1":
297 // void *operator new[](size_t sz) {
298 // printf("%u\n", sz);
299 // return malloc(sz);
301 // void operator delete[](void *p, size_t sz) {
302 // printf("%u\n", sz);
307 // A *p = new A[100];
310 // Whereas it prints "104" and "104" if you give A a destructor.
312 bool requiresArrayCookie(const CXXDeleteExpr *expr,
313 QualType elementType) override;
314 bool requiresArrayCookie(const CXXNewExpr *expr) override;
315 CharUnits getArrayCookieSizeImpl(QualType type) override;
316 llvm::Value *InitializeArrayCookie(CodeGenFunction &CGF,
318 llvm::Value *NumElements,
319 const CXXNewExpr *expr,
320 QualType ElementType) override;
321 llvm::Value *readArrayCookieImpl(CodeGenFunction &CGF,
322 llvm::Value *allocPtr,
323 CharUnits cookieSize) override;
325 friend struct MSRTTIBuilder;
327 bool isImageRelative() const {
328 return CGM.getTarget().getPointerWidth(/*AddressSpace=*/0) == 64;
331 // 5 routines for constructing the llvm types for MS RTTI structs.
332 llvm::StructType *getTypeDescriptorType(StringRef TypeInfoString) {
333 llvm::SmallString<32> TDTypeName("rtti.TypeDescriptor");
334 TDTypeName += llvm::utostr(TypeInfoString.size());
335 llvm::StructType *&TypeDescriptorType =
336 TypeDescriptorTypeMap[TypeInfoString.size()];
337 if (TypeDescriptorType)
338 return TypeDescriptorType;
339 llvm::Type *FieldTypes[] = {
342 llvm::ArrayType::get(CGM.Int8Ty, TypeInfoString.size() + 1)};
344 llvm::StructType::create(CGM.getLLVMContext(), FieldTypes, TDTypeName);
345 return TypeDescriptorType;
348 llvm::Type *getImageRelativeType(llvm::Type *PtrType) {
349 if (!isImageRelative())
354 llvm::StructType *getBaseClassDescriptorType() {
355 if (BaseClassDescriptorType)
356 return BaseClassDescriptorType;
357 llvm::Type *FieldTypes[] = {
358 getImageRelativeType(CGM.Int8PtrTy),
364 getImageRelativeType(getClassHierarchyDescriptorType()->getPointerTo()),
366 BaseClassDescriptorType = llvm::StructType::create(
367 CGM.getLLVMContext(), FieldTypes, "rtti.BaseClassDescriptor");
368 return BaseClassDescriptorType;
371 llvm::StructType *getClassHierarchyDescriptorType() {
372 if (ClassHierarchyDescriptorType)
373 return ClassHierarchyDescriptorType;
374 // Forward-declare RTTIClassHierarchyDescriptor to break a cycle.
375 ClassHierarchyDescriptorType = llvm::StructType::create(
376 CGM.getLLVMContext(), "rtti.ClassHierarchyDescriptor");
377 llvm::Type *FieldTypes[] = {
381 getImageRelativeType(
382 getBaseClassDescriptorType()->getPointerTo()->getPointerTo()),
384 ClassHierarchyDescriptorType->setBody(FieldTypes);
385 return ClassHierarchyDescriptorType;
388 llvm::StructType *getCompleteObjectLocatorType() {
389 if (CompleteObjectLocatorType)
390 return CompleteObjectLocatorType;
391 CompleteObjectLocatorType = llvm::StructType::create(
392 CGM.getLLVMContext(), "rtti.CompleteObjectLocator");
393 llvm::Type *FieldTypes[] = {
397 getImageRelativeType(CGM.Int8PtrTy),
398 getImageRelativeType(getClassHierarchyDescriptorType()->getPointerTo()),
399 getImageRelativeType(CompleteObjectLocatorType),
401 llvm::ArrayRef<llvm::Type *> FieldTypesRef(FieldTypes);
402 if (!isImageRelative())
403 FieldTypesRef = FieldTypesRef.drop_back();
404 CompleteObjectLocatorType->setBody(FieldTypesRef);
405 return CompleteObjectLocatorType;
408 llvm::GlobalVariable *getImageBase() {
409 StringRef Name = "__ImageBase";
410 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(Name))
413 return new llvm::GlobalVariable(CGM.getModule(), CGM.Int8Ty,
415 llvm::GlobalValue::ExternalLinkage,
416 /*Initializer=*/nullptr, Name);
419 llvm::Constant *getImageRelativeConstant(llvm::Constant *PtrVal) {
420 if (!isImageRelative())
423 if (PtrVal->isNullValue())
424 return llvm::Constant::getNullValue(CGM.IntTy);
426 llvm::Constant *ImageBaseAsInt =
427 llvm::ConstantExpr::getPtrToInt(getImageBase(), CGM.IntPtrTy);
428 llvm::Constant *PtrValAsInt =
429 llvm::ConstantExpr::getPtrToInt(PtrVal, CGM.IntPtrTy);
430 llvm::Constant *Diff =
431 llvm::ConstantExpr::getSub(PtrValAsInt, ImageBaseAsInt,
432 /*HasNUW=*/true, /*HasNSW=*/true);
433 return llvm::ConstantExpr::getTrunc(Diff, CGM.IntTy);
437 MicrosoftMangleContext &getMangleContext() {
438 return cast<MicrosoftMangleContext>(CodeGen::CGCXXABI::getMangleContext());
441 llvm::Constant *getZeroInt() {
442 return llvm::ConstantInt::get(CGM.IntTy, 0);
445 llvm::Constant *getAllOnesInt() {
446 return llvm::Constant::getAllOnesValue(CGM.IntTy);
449 llvm::Constant *getConstantOrZeroInt(llvm::Constant *C) {
450 return C ? C : getZeroInt();
453 llvm::Value *getValueOrZeroInt(llvm::Value *C) {
454 return C ? C : getZeroInt();
457 CharUnits getVirtualFunctionPrologueThisAdjustment(GlobalDecl GD);
460 GetNullMemberPointerFields(const MemberPointerType *MPT,
461 llvm::SmallVectorImpl<llvm::Constant *> &fields);
463 /// \brief Shared code for virtual base adjustment. Returns the offset from
464 /// the vbptr to the virtual base. Optionally returns the address of the
466 llvm::Value *GetVBaseOffsetFromVBPtr(CodeGenFunction &CGF,
468 llvm::Value *VBPtrOffset,
469 llvm::Value *VBTableOffset,
470 llvm::Value **VBPtr = nullptr);
472 llvm::Value *GetVBaseOffsetFromVBPtr(CodeGenFunction &CGF,
475 int32_t VBTableOffset,
476 llvm::Value **VBPtr = nullptr) {
477 assert(VBTableOffset % 4 == 0 && "should be byte offset into table of i32s");
478 llvm::Value *VBPOffset = llvm::ConstantInt::get(CGM.IntTy, VBPtrOffset),
479 *VBTOffset = llvm::ConstantInt::get(CGM.IntTy, VBTableOffset);
480 return GetVBaseOffsetFromVBPtr(CGF, Base, VBPOffset, VBTOffset, VBPtr);
483 std::pair<llvm::Value *, llvm::Value *>
484 performBaseAdjustment(CodeGenFunction &CGF, llvm::Value *Value,
485 QualType SrcRecordTy);
487 /// \brief Performs a full virtual base adjustment. Used to dereference
488 /// pointers to members of virtual bases.
489 llvm::Value *AdjustVirtualBase(CodeGenFunction &CGF, const Expr *E,
490 const CXXRecordDecl *RD, llvm::Value *Base,
491 llvm::Value *VirtualBaseAdjustmentOffset,
492 llvm::Value *VBPtrOffset /* optional */);
494 /// \brief Emits a full member pointer with the fields common to data and
495 /// function member pointers.
496 llvm::Constant *EmitFullMemberPointer(llvm::Constant *FirstField,
497 bool IsMemberFunction,
498 const CXXRecordDecl *RD,
499 CharUnits NonVirtualBaseAdjustment);
501 llvm::Constant *BuildMemberPointer(const CXXRecordDecl *RD,
502 const CXXMethodDecl *MD,
503 CharUnits NonVirtualBaseAdjustment);
505 bool MemberPointerConstantIsNull(const MemberPointerType *MPT,
508 /// \brief - Initialize all vbptrs of 'this' with RD as the complete type.
509 void EmitVBPtrStores(CodeGenFunction &CGF, const CXXRecordDecl *RD);
511 /// \brief Caching wrapper around VBTableBuilder::enumerateVBTables().
512 const VBTableGlobals &enumerateVBTables(const CXXRecordDecl *RD);
514 /// \brief Generate a thunk for calling a virtual member function MD.
515 llvm::Function *EmitVirtualMemPtrThunk(
516 const CXXMethodDecl *MD,
517 const MicrosoftVTableContext::MethodVFTableLocation &ML);
520 llvm::Type *ConvertMemberPointerType(const MemberPointerType *MPT) override;
522 bool isZeroInitializable(const MemberPointerType *MPT) override;
524 bool isMemberPointerConvertible(const MemberPointerType *MPT) const override {
525 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
526 return RD->hasAttr<MSInheritanceAttr>();
529 bool isTypeInfoCalculable(QualType Ty) const override {
530 if (!CGCXXABI::isTypeInfoCalculable(Ty))
532 if (const auto *MPT = Ty->getAs<MemberPointerType>()) {
533 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
534 if (!RD->hasAttr<MSInheritanceAttr>())
540 llvm::Constant *EmitNullMemberPointer(const MemberPointerType *MPT) override;
542 llvm::Constant *EmitMemberDataPointer(const MemberPointerType *MPT,
543 CharUnits offset) override;
544 llvm::Constant *EmitMemberPointer(const CXXMethodDecl *MD) override;
545 llvm::Constant *EmitMemberPointer(const APValue &MP, QualType MPT) override;
547 llvm::Value *EmitMemberPointerComparison(CodeGenFunction &CGF,
550 const MemberPointerType *MPT,
551 bool Inequality) override;
553 llvm::Value *EmitMemberPointerIsNotNull(CodeGenFunction &CGF,
555 const MemberPointerType *MPT) override;
558 EmitMemberDataPointerAddress(CodeGenFunction &CGF, const Expr *E,
559 llvm::Value *Base, llvm::Value *MemPtr,
560 const MemberPointerType *MPT) override;
562 llvm::Value *EmitMemberPointerConversion(CodeGenFunction &CGF,
564 llvm::Value *Src) override;
566 llvm::Constant *EmitMemberPointerConversion(const CastExpr *E,
567 llvm::Constant *Src) override;
570 EmitLoadOfMemberFunctionPointer(CodeGenFunction &CGF, const Expr *E,
571 llvm::Value *&This, llvm::Value *MemPtr,
572 const MemberPointerType *MPT) override;
574 void emitCXXStructor(const CXXMethodDecl *MD, StructorType Type) override;
576 llvm::StructType *getCatchHandlerTypeType() {
577 if (!CatchHandlerTypeType) {
578 llvm::Type *FieldTypes[] = {
580 CGM.Int8PtrTy, // TypeDescriptor
582 CatchHandlerTypeType = llvm::StructType::create(
583 CGM.getLLVMContext(), FieldTypes, "eh.CatchHandlerType");
585 return CatchHandlerTypeType;
588 llvm::StructType *getCatchableTypeType() {
589 if (CatchableTypeType)
590 return CatchableTypeType;
591 llvm::Type *FieldTypes[] = {
593 getImageRelativeType(CGM.Int8PtrTy), // TypeDescriptor
594 CGM.IntTy, // NonVirtualAdjustment
595 CGM.IntTy, // OffsetToVBPtr
596 CGM.IntTy, // VBTableIndex
598 getImageRelativeType(CGM.Int8PtrTy) // CopyCtor
600 CatchableTypeType = llvm::StructType::create(
601 CGM.getLLVMContext(), FieldTypes, "eh.CatchableType");
602 return CatchableTypeType;
605 llvm::StructType *getCatchableTypeArrayType(uint32_t NumEntries) {
606 llvm::StructType *&CatchableTypeArrayType =
607 CatchableTypeArrayTypeMap[NumEntries];
608 if (CatchableTypeArrayType)
609 return CatchableTypeArrayType;
611 llvm::SmallString<23> CTATypeName("eh.CatchableTypeArray.");
612 CTATypeName += llvm::utostr(NumEntries);
614 getImageRelativeType(getCatchableTypeType()->getPointerTo());
615 llvm::Type *FieldTypes[] = {
616 CGM.IntTy, // NumEntries
617 llvm::ArrayType::get(CTType, NumEntries) // CatchableTypes
619 CatchableTypeArrayType =
620 llvm::StructType::create(CGM.getLLVMContext(), FieldTypes, CTATypeName);
621 return CatchableTypeArrayType;
624 llvm::StructType *getThrowInfoType() {
626 return ThrowInfoType;
627 llvm::Type *FieldTypes[] = {
629 getImageRelativeType(CGM.Int8PtrTy), // CleanupFn
630 getImageRelativeType(CGM.Int8PtrTy), // ForwardCompat
631 getImageRelativeType(CGM.Int8PtrTy) // CatchableTypeArray
633 ThrowInfoType = llvm::StructType::create(CGM.getLLVMContext(), FieldTypes,
635 return ThrowInfoType;
638 llvm::Constant *getThrowFn() {
639 // _CxxThrowException is passed an exception object and a ThrowInfo object
640 // which describes the exception.
641 llvm::Type *Args[] = {CGM.Int8PtrTy, getThrowInfoType()->getPointerTo()};
642 llvm::FunctionType *FTy =
643 llvm::FunctionType::get(CGM.VoidTy, Args, /*IsVarArgs=*/false);
644 auto *Fn = cast<llvm::Function>(
645 CGM.CreateRuntimeFunction(FTy, "_CxxThrowException"));
646 // _CxxThrowException is stdcall on 32-bit x86 platforms.
647 if (CGM.getTarget().getTriple().getArch() == llvm::Triple::x86)
648 Fn->setCallingConv(llvm::CallingConv::X86_StdCall);
652 llvm::Function *getAddrOfCXXCtorClosure(const CXXConstructorDecl *CD,
655 llvm::Constant *getCatchableType(QualType T,
656 uint32_t NVOffset = 0,
657 int32_t VBPtrOffset = -1,
658 uint32_t VBIndex = 0);
660 llvm::GlobalVariable *getCatchableTypeArray(QualType T);
662 llvm::GlobalVariable *getThrowInfo(QualType T) override;
665 typedef std::pair<const CXXRecordDecl *, CharUnits> VFTableIdTy;
666 typedef llvm::DenseMap<VFTableIdTy, llvm::GlobalVariable *> VTablesMapTy;
667 typedef llvm::DenseMap<VFTableIdTy, llvm::GlobalValue *> VFTablesMapTy;
668 /// \brief All the vftables that have been referenced.
669 VFTablesMapTy VFTablesMap;
670 VTablesMapTy VTablesMap;
672 /// \brief This set holds the record decls we've deferred vtable emission for.
673 llvm::SmallPtrSet<const CXXRecordDecl *, 4> DeferredVFTables;
676 /// \brief All the vbtables which have been referenced.
677 llvm::DenseMap<const CXXRecordDecl *, VBTableGlobals> VBTablesMap;
679 /// Info on the global variable used to guard initialization of static locals.
680 /// The BitIndex field is only used for externally invisible declarations.
682 GuardInfo() : Guard(nullptr), BitIndex(0) {}
683 llvm::GlobalVariable *Guard;
687 /// Map from DeclContext to the current guard variable. We assume that the
688 /// AST is visited in source code order.
689 llvm::DenseMap<const DeclContext *, GuardInfo> GuardVariableMap;
691 llvm::DenseMap<size_t, llvm::StructType *> TypeDescriptorTypeMap;
692 llvm::StructType *BaseClassDescriptorType;
693 llvm::StructType *ClassHierarchyDescriptorType;
694 llvm::StructType *CompleteObjectLocatorType;
696 llvm::DenseMap<QualType, llvm::GlobalVariable *> CatchableTypeArrays;
698 llvm::StructType *CatchableTypeType;
699 llvm::DenseMap<uint32_t, llvm::StructType *> CatchableTypeArrayTypeMap;
700 llvm::StructType *ThrowInfoType;
701 llvm::StructType *CatchHandlerTypeType;
706 CGCXXABI::RecordArgABI
707 MicrosoftCXXABI::getRecordArgABI(const CXXRecordDecl *RD) const {
708 switch (CGM.getTarget().getTriple().getArch()) {
710 // FIXME: Implement for other architectures.
713 case llvm::Triple::x86:
714 // All record arguments are passed in memory on x86. Decide whether to
715 // construct the object directly in argument memory, or to construct the
716 // argument elsewhere and copy the bytes during the call.
718 // If C++ prohibits us from making a copy, construct the arguments directly
719 // into argument memory.
720 if (!canCopyArgument(RD))
721 return RAA_DirectInMemory;
723 // Otherwise, construct the argument into a temporary and copy the bytes
724 // into the outgoing argument memory.
727 case llvm::Triple::x86_64:
728 // Win64 passes objects with non-trivial copy ctors indirectly.
729 if (RD->hasNonTrivialCopyConstructor())
732 // If an object has a destructor, we'd really like to pass it indirectly
733 // because it allows us to elide copies. Unfortunately, MSVC makes that
734 // impossible for small types, which it will pass in a single register or
735 // stack slot. Most objects with dtors are large-ish, so handle that early.
736 // We can't call out all large objects as being indirect because there are
737 // multiple x64 calling conventions and the C++ ABI code shouldn't dictate
738 // how we pass large POD types.
739 if (RD->hasNonTrivialDestructor() &&
740 getContext().getTypeSize(RD->getTypeForDecl()) > 64)
743 // We have a trivial copy constructor or no copy constructors, but we have
744 // to make sure it isn't deleted.
745 bool CopyDeleted = false;
746 for (const CXXConstructorDecl *CD : RD->ctors()) {
747 if (CD->isCopyConstructor()) {
748 assert(CD->isTrivial());
749 // We had at least one undeleted trivial copy ctor. Return directly.
750 if (!CD->isDeleted())
756 // The trivial copy constructor was deleted. Return indirectly.
760 // There were no copy ctors. Return in RAX.
764 llvm_unreachable("invalid enum");
767 void MicrosoftCXXABI::emitVirtualObjectDelete(CodeGenFunction &CGF,
768 const CXXDeleteExpr *DE,
770 QualType ElementType,
771 const CXXDestructorDecl *Dtor) {
772 // FIXME: Provide a source location here even though there's no
773 // CXXMemberCallExpr for dtor call.
774 bool UseGlobalDelete = DE->isGlobalDelete();
775 CXXDtorType DtorType = UseGlobalDelete ? Dtor_Complete : Dtor_Deleting;
776 llvm::Value *MDThis =
777 EmitVirtualDestructorCall(CGF, Dtor, DtorType, Ptr, /*CE=*/nullptr);
779 CGF.EmitDeleteCall(DE->getOperatorDelete(), MDThis, ElementType);
782 void MicrosoftCXXABI::emitRethrow(CodeGenFunction &CGF, bool isNoReturn) {
783 llvm::Value *Args[] = {
784 llvm::ConstantPointerNull::get(CGM.Int8PtrTy),
785 llvm::ConstantPointerNull::get(getThrowInfoType()->getPointerTo())};
786 auto *Fn = getThrowFn();
788 CGF.EmitNoreturnRuntimeCallOrInvoke(Fn, Args);
790 CGF.EmitRuntimeCallOrInvoke(Fn, Args);
794 struct CallEndCatchMSVC : EHScopeStack::Cleanup {
795 CallEndCatchMSVC() {}
796 void Emit(CodeGenFunction &CGF, Flags flags) override {
797 CGF.EmitNounwindRuntimeCall(
798 CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_endcatch));
803 void MicrosoftCXXABI::emitBeginCatch(CodeGenFunction &CGF,
804 const CXXCatchStmt *S) {
805 // In the MS ABI, the runtime handles the copy, and the catch handler is
806 // responsible for destruction.
807 VarDecl *CatchParam = S->getExceptionDecl();
808 llvm::Value *Exn = CGF.getExceptionFromSlot();
809 llvm::Function *BeginCatch =
810 CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_begincatch);
812 // If this is a catch-all or the catch parameter is unnamed, we don't need to
813 // emit an alloca to the object.
814 if (!CatchParam || !CatchParam->getDeclName()) {
815 llvm::Value *Args[2] = {Exn, llvm::Constant::getNullValue(CGF.Int8PtrTy)};
816 CGF.EmitNounwindRuntimeCall(BeginCatch, Args);
817 CGF.EHStack.pushCleanup<CallEndCatchMSVC>(NormalAndEHCleanup);
821 CodeGenFunction::AutoVarEmission var = CGF.EmitAutoVarAlloca(*CatchParam);
822 llvm::Value *ParamAddr =
823 CGF.Builder.CreateBitCast(var.getObjectAddress(CGF), CGF.Int8PtrTy);
824 llvm::Value *Args[2] = {Exn, ParamAddr};
825 CGF.EmitNounwindRuntimeCall(BeginCatch, Args);
826 // FIXME: Do we really need exceptional endcatch cleanups?
827 CGF.EHStack.pushCleanup<CallEndCatchMSVC>(NormalAndEHCleanup);
828 CGF.EmitAutoVarCleanups(var);
831 std::pair<llvm::Value *, llvm::Value *>
832 MicrosoftCXXABI::performBaseAdjustment(CodeGenFunction &CGF, llvm::Value *Value,
833 QualType SrcRecordTy) {
834 Value = CGF.Builder.CreateBitCast(Value, CGF.Int8PtrTy);
835 const CXXRecordDecl *SrcDecl = SrcRecordTy->getAsCXXRecordDecl();
836 const ASTContext &Context = getContext();
838 if (Context.getASTRecordLayout(SrcDecl).hasExtendableVFPtr())
839 return std::make_pair(Value, llvm::ConstantInt::get(CGF.Int32Ty, 0));
841 // Perform a base adjustment.
842 const CXXBaseSpecifier *PolymorphicBase = std::find_if(
843 SrcDecl->vbases_begin(), SrcDecl->vbases_end(),
844 [&](const CXXBaseSpecifier &Base) {
845 const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
846 return Context.getASTRecordLayout(BaseDecl).hasExtendableVFPtr();
848 llvm::Value *Offset = GetVirtualBaseClassOffset(
849 CGF, Value, SrcDecl, PolymorphicBase->getType()->getAsCXXRecordDecl());
850 Value = CGF.Builder.CreateInBoundsGEP(Value, Offset);
851 Offset = CGF.Builder.CreateTrunc(Offset, CGF.Int32Ty);
852 return std::make_pair(Value, Offset);
855 bool MicrosoftCXXABI::shouldTypeidBeNullChecked(bool IsDeref,
856 QualType SrcRecordTy) {
857 const CXXRecordDecl *SrcDecl = SrcRecordTy->getAsCXXRecordDecl();
859 !getContext().getASTRecordLayout(SrcDecl).hasExtendableVFPtr();
862 static llvm::CallSite emitRTtypeidCall(CodeGenFunction &CGF,
863 llvm::Value *Argument) {
864 llvm::Type *ArgTypes[] = {CGF.Int8PtrTy};
865 llvm::FunctionType *FTy =
866 llvm::FunctionType::get(CGF.Int8PtrTy, ArgTypes, false);
867 llvm::Value *Args[] = {Argument};
868 llvm::Constant *Fn = CGF.CGM.CreateRuntimeFunction(FTy, "__RTtypeid");
869 return CGF.EmitRuntimeCallOrInvoke(Fn, Args);
872 void MicrosoftCXXABI::EmitBadTypeidCall(CodeGenFunction &CGF) {
873 llvm::CallSite Call =
874 emitRTtypeidCall(CGF, llvm::Constant::getNullValue(CGM.VoidPtrTy));
875 Call.setDoesNotReturn();
876 CGF.Builder.CreateUnreachable();
879 llvm::Value *MicrosoftCXXABI::EmitTypeid(CodeGenFunction &CGF,
880 QualType SrcRecordTy,
881 llvm::Value *ThisPtr,
882 llvm::Type *StdTypeInfoPtrTy) {
884 std::tie(ThisPtr, Offset) = performBaseAdjustment(CGF, ThisPtr, SrcRecordTy);
885 return CGF.Builder.CreateBitCast(
886 emitRTtypeidCall(CGF, ThisPtr).getInstruction(), StdTypeInfoPtrTy);
889 bool MicrosoftCXXABI::shouldDynamicCastCallBeNullChecked(bool SrcIsPtr,
890 QualType SrcRecordTy) {
891 const CXXRecordDecl *SrcDecl = SrcRecordTy->getAsCXXRecordDecl();
893 !getContext().getASTRecordLayout(SrcDecl).hasExtendableVFPtr();
896 llvm::Value *MicrosoftCXXABI::EmitDynamicCastCall(
897 CodeGenFunction &CGF, llvm::Value *Value, QualType SrcRecordTy,
898 QualType DestTy, QualType DestRecordTy, llvm::BasicBlock *CastEnd) {
899 llvm::Type *DestLTy = CGF.ConvertType(DestTy);
901 llvm::Value *SrcRTTI =
902 CGF.CGM.GetAddrOfRTTIDescriptor(SrcRecordTy.getUnqualifiedType());
903 llvm::Value *DestRTTI =
904 CGF.CGM.GetAddrOfRTTIDescriptor(DestRecordTy.getUnqualifiedType());
907 std::tie(Value, Offset) = performBaseAdjustment(CGF, Value, SrcRecordTy);
909 // PVOID __RTDynamicCast(
915 llvm::Type *ArgTypes[] = {CGF.Int8PtrTy, CGF.Int32Ty, CGF.Int8PtrTy,
916 CGF.Int8PtrTy, CGF.Int32Ty};
917 llvm::Constant *Function = CGF.CGM.CreateRuntimeFunction(
918 llvm::FunctionType::get(CGF.Int8PtrTy, ArgTypes, false),
920 llvm::Value *Args[] = {
921 Value, Offset, SrcRTTI, DestRTTI,
922 llvm::ConstantInt::get(CGF.Int32Ty, DestTy->isReferenceType())};
923 Value = CGF.EmitRuntimeCallOrInvoke(Function, Args).getInstruction();
924 return CGF.Builder.CreateBitCast(Value, DestLTy);
928 MicrosoftCXXABI::EmitDynamicCastToVoid(CodeGenFunction &CGF, llvm::Value *Value,
929 QualType SrcRecordTy,
932 std::tie(Value, Offset) = performBaseAdjustment(CGF, Value, SrcRecordTy);
934 // PVOID __RTCastToVoid(
936 llvm::Type *ArgTypes[] = {CGF.Int8PtrTy};
937 llvm::Constant *Function = CGF.CGM.CreateRuntimeFunction(
938 llvm::FunctionType::get(CGF.Int8PtrTy, ArgTypes, false),
940 llvm::Value *Args[] = {Value};
941 return CGF.EmitRuntimeCall(Function, Args);
944 bool MicrosoftCXXABI::EmitBadCastCall(CodeGenFunction &CGF) {
948 llvm::Value *MicrosoftCXXABI::GetVirtualBaseClassOffset(
949 CodeGenFunction &CGF, llvm::Value *This, const CXXRecordDecl *ClassDecl,
950 const CXXRecordDecl *BaseClassDecl) {
951 const ASTContext &Context = getContext();
953 Context.getASTRecordLayout(ClassDecl).getVBPtrOffset().getQuantity();
954 llvm::Value *VBPtrOffset = llvm::ConstantInt::get(CGM.PtrDiffTy, VBPtrChars);
955 CharUnits IntSize = Context.getTypeSizeInChars(Context.IntTy);
956 CharUnits VBTableChars =
958 CGM.getMicrosoftVTableContext().getVBTableIndex(ClassDecl, BaseClassDecl);
959 llvm::Value *VBTableOffset =
960 llvm::ConstantInt::get(CGM.IntTy, VBTableChars.getQuantity());
962 llvm::Value *VBPtrToNewBase =
963 GetVBaseOffsetFromVBPtr(CGF, This, VBPtrOffset, VBTableOffset);
965 CGF.Builder.CreateSExtOrBitCast(VBPtrToNewBase, CGM.PtrDiffTy);
966 return CGF.Builder.CreateNSWAdd(VBPtrOffset, VBPtrToNewBase);
969 bool MicrosoftCXXABI::HasThisReturn(GlobalDecl GD) const {
970 return isa<CXXConstructorDecl>(GD.getDecl());
973 static bool isDeletingDtor(GlobalDecl GD) {
974 return isa<CXXDestructorDecl>(GD.getDecl()) &&
975 GD.getDtorType() == Dtor_Deleting;
978 bool MicrosoftCXXABI::hasMostDerivedReturn(GlobalDecl GD) const {
979 return isDeletingDtor(GD);
982 bool MicrosoftCXXABI::classifyReturnType(CGFunctionInfo &FI) const {
983 const CXXRecordDecl *RD = FI.getReturnType()->getAsCXXRecordDecl();
987 if (FI.isInstanceMethod()) {
988 // If it's an instance method, aggregates are always returned indirectly via
989 // the second parameter.
990 FI.getReturnInfo() = ABIArgInfo::getIndirect(0, /*ByVal=*/false);
991 FI.getReturnInfo().setSRetAfterThis(FI.isInstanceMethod());
993 } else if (!RD->isPOD()) {
994 // If it's a free function, non-POD types are returned indirectly.
995 FI.getReturnInfo() = ABIArgInfo::getIndirect(0, /*ByVal=*/false);
999 // Otherwise, use the C ABI rules.
1004 MicrosoftCXXABI::EmitCtorCompleteObjectHandler(CodeGenFunction &CGF,
1005 const CXXRecordDecl *RD) {
1006 llvm::Value *IsMostDerivedClass = getStructorImplicitParamValue(CGF);
1007 assert(IsMostDerivedClass &&
1008 "ctor for a class with virtual bases must have an implicit parameter");
1009 llvm::Value *IsCompleteObject =
1010 CGF.Builder.CreateIsNotNull(IsMostDerivedClass, "is_complete_object");
1012 llvm::BasicBlock *CallVbaseCtorsBB = CGF.createBasicBlock("ctor.init_vbases");
1013 llvm::BasicBlock *SkipVbaseCtorsBB = CGF.createBasicBlock("ctor.skip_vbases");
1014 CGF.Builder.CreateCondBr(IsCompleteObject,
1015 CallVbaseCtorsBB, SkipVbaseCtorsBB);
1017 CGF.EmitBlock(CallVbaseCtorsBB);
1019 // Fill in the vbtable pointers here.
1020 EmitVBPtrStores(CGF, RD);
1022 // CGF will put the base ctor calls in this basic block for us later.
1024 return SkipVbaseCtorsBB;
1027 void MicrosoftCXXABI::initializeHiddenVirtualInheritanceMembers(
1028 CodeGenFunction &CGF, const CXXRecordDecl *RD) {
1029 // In most cases, an override for a vbase virtual method can adjust
1030 // the "this" parameter by applying a constant offset.
1031 // However, this is not enough while a constructor or a destructor of some
1032 // class X is being executed if all the following conditions are met:
1033 // - X has virtual bases, (1)
1034 // - X overrides a virtual method M of a vbase Y, (2)
1035 // - X itself is a vbase of the most derived class.
1037 // If (1) and (2) are true, the vtorDisp for vbase Y is a hidden member of X
1038 // which holds the extra amount of "this" adjustment we must do when we use
1039 // the X vftables (i.e. during X ctor or dtor).
1040 // Outside the ctors and dtors, the values of vtorDisps are zero.
1042 const ASTRecordLayout &Layout = getContext().getASTRecordLayout(RD);
1043 typedef ASTRecordLayout::VBaseOffsetsMapTy VBOffsets;
1044 const VBOffsets &VBaseMap = Layout.getVBaseOffsetsMap();
1045 CGBuilderTy &Builder = CGF.Builder;
1048 cast<llvm::PointerType>(getThisValue(CGF)->getType())->getAddressSpace();
1049 llvm::Value *Int8This = nullptr; // Initialize lazily.
1051 for (VBOffsets::const_iterator I = VBaseMap.begin(), E = VBaseMap.end();
1053 if (!I->second.hasVtorDisp())
1056 llvm::Value *VBaseOffset =
1057 GetVirtualBaseClassOffset(CGF, getThisValue(CGF), RD, I->first);
1058 // FIXME: it doesn't look right that we SExt in GetVirtualBaseClassOffset()
1059 // just to Trunc back immediately.
1060 VBaseOffset = Builder.CreateTruncOrBitCast(VBaseOffset, CGF.Int32Ty);
1061 uint64_t ConstantVBaseOffset =
1062 Layout.getVBaseClassOffset(I->first).getQuantity();
1064 // vtorDisp_for_vbase = vbptr[vbase_idx] - offsetof(RD, vbase).
1065 llvm::Value *VtorDispValue = Builder.CreateSub(
1066 VBaseOffset, llvm::ConstantInt::get(CGM.Int32Ty, ConstantVBaseOffset),
1070 Int8This = Builder.CreateBitCast(getThisValue(CGF),
1071 CGF.Int8Ty->getPointerTo(AS));
1072 llvm::Value *VtorDispPtr = Builder.CreateInBoundsGEP(Int8This, VBaseOffset);
1073 // vtorDisp is always the 32-bits before the vbase in the class layout.
1074 VtorDispPtr = Builder.CreateConstGEP1_32(VtorDispPtr, -4);
1075 VtorDispPtr = Builder.CreateBitCast(
1076 VtorDispPtr, CGF.Int32Ty->getPointerTo(AS), "vtordisp.ptr");
1078 Builder.CreateStore(VtorDispValue, VtorDispPtr);
1082 static bool hasDefaultCXXMethodCC(ASTContext &Context,
1083 const CXXMethodDecl *MD) {
1084 CallingConv ExpectedCallingConv = Context.getDefaultCallingConvention(
1085 /*IsVariadic=*/false, /*IsCXXMethod=*/true);
1086 CallingConv ActualCallingConv =
1087 MD->getType()->getAs<FunctionProtoType>()->getCallConv();
1088 return ExpectedCallingConv == ActualCallingConv;
1091 void MicrosoftCXXABI::EmitCXXConstructors(const CXXConstructorDecl *D) {
1092 // There's only one constructor type in this ABI.
1093 CGM.EmitGlobal(GlobalDecl(D, Ctor_Complete));
1095 // Exported default constructors either have a simple call-site where they use
1096 // the typical calling convention and have a single 'this' pointer for an
1097 // argument -or- they get a wrapper function which appropriately thunks to the
1098 // real default constructor. This thunk is the default constructor closure.
1099 if (D->hasAttr<DLLExportAttr>() && D->isDefaultConstructor())
1100 if (!hasDefaultCXXMethodCC(getContext(), D) || D->getNumParams() != 0) {
1101 llvm::Function *Fn = getAddrOfCXXCtorClosure(D, Ctor_DefaultClosure);
1102 Fn->setLinkage(llvm::GlobalValue::WeakODRLinkage);
1103 Fn->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
1107 void MicrosoftCXXABI::EmitVBPtrStores(CodeGenFunction &CGF,
1108 const CXXRecordDecl *RD) {
1109 llvm::Value *ThisInt8Ptr =
1110 CGF.Builder.CreateBitCast(getThisValue(CGF), CGM.Int8PtrTy, "this.int8");
1111 const ASTContext &Context = getContext();
1112 const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
1114 const VBTableGlobals &VBGlobals = enumerateVBTables(RD);
1115 for (unsigned I = 0, E = VBGlobals.VBTables->size(); I != E; ++I) {
1116 const VPtrInfo *VBT = (*VBGlobals.VBTables)[I];
1117 llvm::GlobalVariable *GV = VBGlobals.Globals[I];
1118 const ASTRecordLayout &SubobjectLayout =
1119 Context.getASTRecordLayout(VBT->BaseWithVPtr);
1120 CharUnits Offs = VBT->NonVirtualOffset;
1121 Offs += SubobjectLayout.getVBPtrOffset();
1122 if (VBT->getVBaseWithVPtr())
1123 Offs += Layout.getVBaseClassOffset(VBT->getVBaseWithVPtr());
1124 llvm::Value *VBPtr =
1125 CGF.Builder.CreateConstInBoundsGEP1_64(ThisInt8Ptr, Offs.getQuantity());
1126 llvm::Value *GVPtr =
1127 CGF.Builder.CreateConstInBoundsGEP2_32(GV->getValueType(), GV, 0, 0);
1128 VBPtr = CGF.Builder.CreateBitCast(VBPtr, GVPtr->getType()->getPointerTo(0),
1129 "vbptr." + VBT->ReusingBase->getName());
1130 CGF.Builder.CreateStore(GVPtr, VBPtr);
1135 MicrosoftCXXABI::buildStructorSignature(const CXXMethodDecl *MD, StructorType T,
1136 SmallVectorImpl<CanQualType> &ArgTys) {
1137 // TODO: 'for base' flag
1138 if (T == StructorType::Deleting) {
1139 // The scalar deleting destructor takes an implicit int parameter.
1140 ArgTys.push_back(getContext().IntTy);
1142 auto *CD = dyn_cast<CXXConstructorDecl>(MD);
1146 // All parameters are already in place except is_most_derived, which goes
1147 // after 'this' if it's variadic and last if it's not.
1149 const CXXRecordDecl *Class = CD->getParent();
1150 const FunctionProtoType *FPT = CD->getType()->castAs<FunctionProtoType>();
1151 if (Class->getNumVBases()) {
1152 if (FPT->isVariadic())
1153 ArgTys.insert(ArgTys.begin() + 1, getContext().IntTy);
1155 ArgTys.push_back(getContext().IntTy);
1159 void MicrosoftCXXABI::EmitCXXDestructors(const CXXDestructorDecl *D) {
1160 // The TU defining a dtor is only guaranteed to emit a base destructor. All
1161 // other destructor variants are delegating thunks.
1162 CGM.EmitGlobal(GlobalDecl(D, Dtor_Base));
1166 MicrosoftCXXABI::getVirtualFunctionPrologueThisAdjustment(GlobalDecl GD) {
1167 GD = GD.getCanonicalDecl();
1168 const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
1170 GlobalDecl LookupGD = GD;
1171 if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(MD)) {
1172 // Complete destructors take a pointer to the complete object as a
1173 // parameter, thus don't need this adjustment.
1174 if (GD.getDtorType() == Dtor_Complete)
1177 // There's no Dtor_Base in vftable but it shares the this adjustment with
1178 // the deleting one, so look it up instead.
1179 LookupGD = GlobalDecl(DD, Dtor_Deleting);
1182 MicrosoftVTableContext::MethodVFTableLocation ML =
1183 CGM.getMicrosoftVTableContext().getMethodVFTableLocation(LookupGD);
1184 CharUnits Adjustment = ML.VFPtrOffset;
1186 // Normal virtual instance methods need to adjust from the vfptr that first
1187 // defined the virtual method to the virtual base subobject, but destructors
1188 // do not. The vector deleting destructor thunk applies this adjustment for
1190 if (isa<CXXDestructorDecl>(MD))
1191 Adjustment = CharUnits::Zero();
1194 const ASTRecordLayout &DerivedLayout =
1195 getContext().getASTRecordLayout(MD->getParent());
1196 Adjustment += DerivedLayout.getVBaseClassOffset(ML.VBase);
1202 llvm::Value *MicrosoftCXXABI::adjustThisArgumentForVirtualFunctionCall(
1203 CodeGenFunction &CGF, GlobalDecl GD, llvm::Value *This, bool VirtualCall) {
1205 // If the call of a virtual function is not virtual, we just have to
1206 // compensate for the adjustment the virtual function does in its prologue.
1207 CharUnits Adjustment = getVirtualFunctionPrologueThisAdjustment(GD);
1208 if (Adjustment.isZero())
1211 unsigned AS = cast<llvm::PointerType>(This->getType())->getAddressSpace();
1212 llvm::Type *charPtrTy = CGF.Int8Ty->getPointerTo(AS);
1213 This = CGF.Builder.CreateBitCast(This, charPtrTy);
1214 assert(Adjustment.isPositive());
1215 return CGF.Builder.CreateConstGEP1_32(This, Adjustment.getQuantity());
1218 GD = GD.getCanonicalDecl();
1219 const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
1221 GlobalDecl LookupGD = GD;
1222 if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(MD)) {
1223 // Complete dtors take a pointer to the complete object,
1224 // thus don't need adjustment.
1225 if (GD.getDtorType() == Dtor_Complete)
1228 // There's only Dtor_Deleting in vftable but it shares the this adjustment
1229 // with the base one, so look up the deleting one instead.
1230 LookupGD = GlobalDecl(DD, Dtor_Deleting);
1232 MicrosoftVTableContext::MethodVFTableLocation ML =
1233 CGM.getMicrosoftVTableContext().getMethodVFTableLocation(LookupGD);
1235 unsigned AS = cast<llvm::PointerType>(This->getType())->getAddressSpace();
1236 llvm::Type *charPtrTy = CGF.Int8Ty->getPointerTo(AS);
1237 CharUnits StaticOffset = ML.VFPtrOffset;
1239 // Base destructors expect 'this' to point to the beginning of the base
1240 // subobject, not the first vfptr that happens to contain the virtual dtor.
1241 // However, we still need to apply the virtual base adjustment.
1242 if (isa<CXXDestructorDecl>(MD) && GD.getDtorType() == Dtor_Base)
1243 StaticOffset = CharUnits::Zero();
1246 This = CGF.Builder.CreateBitCast(This, charPtrTy);
1247 llvm::Value *VBaseOffset =
1248 GetVirtualBaseClassOffset(CGF, This, MD->getParent(), ML.VBase);
1249 This = CGF.Builder.CreateInBoundsGEP(This, VBaseOffset);
1251 if (!StaticOffset.isZero()) {
1252 assert(StaticOffset.isPositive());
1253 This = CGF.Builder.CreateBitCast(This, charPtrTy);
1255 // Non-virtual adjustment might result in a pointer outside the allocated
1256 // object, e.g. if the final overrider class is laid out after the virtual
1257 // base that declares a method in the most derived class.
1258 // FIXME: Update the code that emits this adjustment in thunks prologues.
1259 This = CGF.Builder.CreateConstGEP1_32(This, StaticOffset.getQuantity());
1261 This = CGF.Builder.CreateConstInBoundsGEP1_32(CGF.Int8Ty, This,
1262 StaticOffset.getQuantity());
1268 void MicrosoftCXXABI::addImplicitStructorParams(CodeGenFunction &CGF,
1270 FunctionArgList &Params) {
1271 ASTContext &Context = getContext();
1272 const CXXMethodDecl *MD = cast<CXXMethodDecl>(CGF.CurGD.getDecl());
1273 assert(isa<CXXConstructorDecl>(MD) || isa<CXXDestructorDecl>(MD));
1274 if (isa<CXXConstructorDecl>(MD) && MD->getParent()->getNumVBases()) {
1275 ImplicitParamDecl *IsMostDerived
1276 = ImplicitParamDecl::Create(Context, nullptr,
1277 CGF.CurGD.getDecl()->getLocation(),
1278 &Context.Idents.get("is_most_derived"),
1280 // The 'most_derived' parameter goes second if the ctor is variadic and last
1281 // if it's not. Dtors can't be variadic.
1282 const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>();
1283 if (FPT->isVariadic())
1284 Params.insert(Params.begin() + 1, IsMostDerived);
1286 Params.push_back(IsMostDerived);
1287 getStructorImplicitParamDecl(CGF) = IsMostDerived;
1288 } else if (isDeletingDtor(CGF.CurGD)) {
1289 ImplicitParamDecl *ShouldDelete
1290 = ImplicitParamDecl::Create(Context, nullptr,
1291 CGF.CurGD.getDecl()->getLocation(),
1292 &Context.Idents.get("should_call_delete"),
1294 Params.push_back(ShouldDelete);
1295 getStructorImplicitParamDecl(CGF) = ShouldDelete;
1299 llvm::Value *MicrosoftCXXABI::adjustThisParameterInVirtualFunctionPrologue(
1300 CodeGenFunction &CGF, GlobalDecl GD, llvm::Value *This) {
1301 // In this ABI, every virtual function takes a pointer to one of the
1302 // subobjects that first defines it as the 'this' parameter, rather than a
1303 // pointer to the final overrider subobject. Thus, we need to adjust it back
1304 // to the final overrider subobject before use.
1305 // See comments in the MicrosoftVFTableContext implementation for the details.
1306 CharUnits Adjustment = getVirtualFunctionPrologueThisAdjustment(GD);
1307 if (Adjustment.isZero())
1310 unsigned AS = cast<llvm::PointerType>(This->getType())->getAddressSpace();
1311 llvm::Type *charPtrTy = CGF.Int8Ty->getPointerTo(AS),
1312 *thisTy = This->getType();
1314 This = CGF.Builder.CreateBitCast(This, charPtrTy);
1315 assert(Adjustment.isPositive());
1316 This = CGF.Builder.CreateConstInBoundsGEP1_32(CGF.Int8Ty, This,
1317 -Adjustment.getQuantity());
1318 return CGF.Builder.CreateBitCast(This, thisTy);
1321 void MicrosoftCXXABI::EmitInstanceFunctionProlog(CodeGenFunction &CGF) {
1324 /// If this is a function that the ABI specifies returns 'this', initialize
1325 /// the return slot to 'this' at the start of the function.
1327 /// Unlike the setting of return types, this is done within the ABI
1328 /// implementation instead of by clients of CGCXXABI because:
1329 /// 1) getThisValue is currently protected
1330 /// 2) in theory, an ABI could implement 'this' returns some other way;
1331 /// HasThisReturn only specifies a contract, not the implementation
1332 if (HasThisReturn(CGF.CurGD))
1333 CGF.Builder.CreateStore(getThisValue(CGF), CGF.ReturnValue);
1334 else if (hasMostDerivedReturn(CGF.CurGD))
1335 CGF.Builder.CreateStore(CGF.EmitCastToVoidPtr(getThisValue(CGF)),
1338 const CXXMethodDecl *MD = cast<CXXMethodDecl>(CGF.CurGD.getDecl());
1339 if (isa<CXXConstructorDecl>(MD) && MD->getParent()->getNumVBases()) {
1340 assert(getStructorImplicitParamDecl(CGF) &&
1341 "no implicit parameter for a constructor with virtual bases?");
1342 getStructorImplicitParamValue(CGF)
1343 = CGF.Builder.CreateLoad(
1344 CGF.GetAddrOfLocalVar(getStructorImplicitParamDecl(CGF)),
1348 if (isDeletingDtor(CGF.CurGD)) {
1349 assert(getStructorImplicitParamDecl(CGF) &&
1350 "no implicit parameter for a deleting destructor?");
1351 getStructorImplicitParamValue(CGF)
1352 = CGF.Builder.CreateLoad(
1353 CGF.GetAddrOfLocalVar(getStructorImplicitParamDecl(CGF)),
1354 "should_call_delete");
1358 unsigned MicrosoftCXXABI::addImplicitConstructorArgs(
1359 CodeGenFunction &CGF, const CXXConstructorDecl *D, CXXCtorType Type,
1360 bool ForVirtualBase, bool Delegating, CallArgList &Args) {
1361 assert(Type == Ctor_Complete || Type == Ctor_Base);
1363 // Check if we need a 'most_derived' parameter.
1364 if (!D->getParent()->getNumVBases())
1367 // Add the 'most_derived' argument second if we are variadic or last if not.
1368 const FunctionProtoType *FPT = D->getType()->castAs<FunctionProtoType>();
1369 llvm::Value *MostDerivedArg =
1370 llvm::ConstantInt::get(CGM.Int32Ty, Type == Ctor_Complete);
1371 RValue RV = RValue::get(MostDerivedArg);
1372 if (MostDerivedArg) {
1373 if (FPT->isVariadic())
1374 Args.insert(Args.begin() + 1,
1375 CallArg(RV, getContext().IntTy, /*needscopy=*/false));
1377 Args.add(RV, getContext().IntTy);
1380 return 1; // Added one arg.
1383 void MicrosoftCXXABI::EmitDestructorCall(CodeGenFunction &CGF,
1384 const CXXDestructorDecl *DD,
1385 CXXDtorType Type, bool ForVirtualBase,
1386 bool Delegating, llvm::Value *This) {
1387 llvm::Value *Callee = CGM.getAddrOfCXXStructor(DD, getFromDtorType(Type));
1389 if (DD->isVirtual()) {
1390 assert(Type != CXXDtorType::Dtor_Deleting &&
1391 "The deleting destructor should only be called via a virtual call");
1392 This = adjustThisArgumentForVirtualFunctionCall(CGF, GlobalDecl(DD, Type),
1396 CGF.EmitCXXStructorCall(DD, Callee, ReturnValueSlot(), This,
1397 /*ImplicitParam=*/nullptr,
1398 /*ImplicitParamTy=*/QualType(), nullptr,
1399 getFromDtorType(Type));
1402 void MicrosoftCXXABI::emitVTableDefinitions(CodeGenVTables &CGVT,
1403 const CXXRecordDecl *RD) {
1404 MicrosoftVTableContext &VFTContext = CGM.getMicrosoftVTableContext();
1405 const VPtrInfoVector &VFPtrs = VFTContext.getVFPtrOffsets(RD);
1407 for (VPtrInfo *Info : VFPtrs) {
1408 llvm::GlobalVariable *VTable = getAddrOfVTable(RD, Info->FullOffsetInMDC);
1409 if (VTable->hasInitializer())
1412 llvm::Constant *RTTI = getContext().getLangOpts().RTTIData
1413 ? getMSCompleteObjectLocator(RD, Info)
1416 const VTableLayout &VTLayout =
1417 VFTContext.getVFTableLayout(RD, Info->FullOffsetInMDC);
1418 llvm::Constant *Init = CGVT.CreateVTableInitializer(
1419 RD, VTLayout.vtable_component_begin(),
1420 VTLayout.getNumVTableComponents(), VTLayout.vtable_thunk_begin(),
1421 VTLayout.getNumVTableThunks(), RTTI);
1423 VTable->setInitializer(Init);
1427 llvm::Value *MicrosoftCXXABI::getVTableAddressPointInStructor(
1428 CodeGenFunction &CGF, const CXXRecordDecl *VTableClass, BaseSubobject Base,
1429 const CXXRecordDecl *NearestVBase, bool &NeedsVirtualOffset) {
1430 NeedsVirtualOffset = (NearestVBase != nullptr);
1432 (void)getAddrOfVTable(VTableClass, Base.getBaseOffset());
1433 VFTableIdTy ID(VTableClass, Base.getBaseOffset());
1434 llvm::GlobalValue *VTableAddressPoint = VFTablesMap[ID];
1435 if (!VTableAddressPoint) {
1436 assert(Base.getBase()->getNumVBases() &&
1437 !getContext().getASTRecordLayout(Base.getBase()).hasOwnVFPtr());
1439 return VTableAddressPoint;
1442 static void mangleVFTableName(MicrosoftMangleContext &MangleContext,
1443 const CXXRecordDecl *RD, const VPtrInfo *VFPtr,
1444 SmallString<256> &Name) {
1445 llvm::raw_svector_ostream Out(Name);
1446 MangleContext.mangleCXXVFTable(RD, VFPtr->MangledPath, Out);
1449 llvm::Constant *MicrosoftCXXABI::getVTableAddressPointForConstExpr(
1450 BaseSubobject Base, const CXXRecordDecl *VTableClass) {
1451 (void)getAddrOfVTable(VTableClass, Base.getBaseOffset());
1452 VFTableIdTy ID(VTableClass, Base.getBaseOffset());
1453 llvm::GlobalValue *VFTable = VFTablesMap[ID];
1454 assert(VFTable && "Couldn't find a vftable for the given base?");
1458 llvm::GlobalVariable *MicrosoftCXXABI::getAddrOfVTable(const CXXRecordDecl *RD,
1459 CharUnits VPtrOffset) {
1460 // getAddrOfVTable may return 0 if asked to get an address of a vtable which
1461 // shouldn't be used in the given record type. We want to cache this result in
1462 // VFTablesMap, thus a simple zero check is not sufficient.
1463 VFTableIdTy ID(RD, VPtrOffset);
1464 VTablesMapTy::iterator I;
1466 std::tie(I, Inserted) = VTablesMap.insert(std::make_pair(ID, nullptr));
1470 llvm::GlobalVariable *&VTable = I->second;
1472 MicrosoftVTableContext &VTContext = CGM.getMicrosoftVTableContext();
1473 const VPtrInfoVector &VFPtrs = VTContext.getVFPtrOffsets(RD);
1475 if (DeferredVFTables.insert(RD).second) {
1476 // We haven't processed this record type before.
1477 // Queue up this v-table for possible deferred emission.
1478 CGM.addDeferredVTable(RD);
1481 // Create all the vftables at once in order to make sure each vftable has
1482 // a unique mangled name.
1483 llvm::StringSet<> ObservedMangledNames;
1484 for (size_t J = 0, F = VFPtrs.size(); J != F; ++J) {
1485 SmallString<256> Name;
1486 mangleVFTableName(getMangleContext(), RD, VFPtrs[J], Name);
1487 if (!ObservedMangledNames.insert(Name.str()).second)
1488 llvm_unreachable("Already saw this mangling before?");
1493 VPtrInfo *const *VFPtrI =
1494 std::find_if(VFPtrs.begin(), VFPtrs.end(), [&](VPtrInfo *VPI) {
1495 return VPI->FullOffsetInMDC == VPtrOffset;
1497 if (VFPtrI == VFPtrs.end()) {
1498 VFTablesMap[ID] = nullptr;
1501 VPtrInfo *VFPtr = *VFPtrI;
1503 SmallString<256> VFTableName;
1504 mangleVFTableName(getMangleContext(), RD, VFPtr, VFTableName);
1506 llvm::GlobalValue::LinkageTypes VFTableLinkage = CGM.getVTableLinkage(RD);
1507 bool VFTableComesFromAnotherTU =
1508 llvm::GlobalValue::isAvailableExternallyLinkage(VFTableLinkage) ||
1509 llvm::GlobalValue::isExternalLinkage(VFTableLinkage);
1510 bool VTableAliasIsRequred =
1511 !VFTableComesFromAnotherTU && getContext().getLangOpts().RTTIData;
1513 if (llvm::GlobalValue *VFTable =
1514 CGM.getModule().getNamedGlobal(VFTableName)) {
1515 VFTablesMap[ID] = VFTable;
1516 return VTableAliasIsRequred
1517 ? cast<llvm::GlobalVariable>(
1518 cast<llvm::GlobalAlias>(VFTable)->getBaseObject())
1519 : cast<llvm::GlobalVariable>(VFTable);
1522 uint64_t NumVTableSlots =
1523 VTContext.getVFTableLayout(RD, VFPtr->FullOffsetInMDC)
1524 .getNumVTableComponents();
1525 llvm::GlobalValue::LinkageTypes VTableLinkage =
1526 VTableAliasIsRequred ? llvm::GlobalValue::PrivateLinkage : VFTableLinkage;
1528 StringRef VTableName = VTableAliasIsRequred ? StringRef() : VFTableName.str();
1530 llvm::ArrayType *VTableType =
1531 llvm::ArrayType::get(CGM.Int8PtrTy, NumVTableSlots);
1533 // Create a backing variable for the contents of VTable. The VTable may
1534 // or may not include space for a pointer to RTTI data.
1535 llvm::GlobalValue *VFTable;
1536 VTable = new llvm::GlobalVariable(CGM.getModule(), VTableType,
1537 /*isConstant=*/true, VTableLinkage,
1538 /*Initializer=*/nullptr, VTableName);
1539 VTable->setUnnamedAddr(true);
1541 llvm::Comdat *C = nullptr;
1542 if (!VFTableComesFromAnotherTU &&
1543 (llvm::GlobalValue::isWeakForLinker(VFTableLinkage) ||
1544 (llvm::GlobalValue::isLocalLinkage(VFTableLinkage) &&
1545 VTableAliasIsRequred)))
1546 C = CGM.getModule().getOrInsertComdat(VFTableName.str());
1548 // Only insert a pointer into the VFTable for RTTI data if we are not
1549 // importing it. We never reference the RTTI data directly so there is no
1550 // need to make room for it.
1551 if (VTableAliasIsRequred) {
1552 llvm::Value *GEPIndices[] = {llvm::ConstantInt::get(CGM.IntTy, 0),
1553 llvm::ConstantInt::get(CGM.IntTy, 1)};
1554 // Create a GEP which points just after the first entry in the VFTable,
1555 // this should be the location of the first virtual method.
1556 llvm::Constant *VTableGEP = llvm::ConstantExpr::getInBoundsGetElementPtr(
1557 VTable->getValueType(), VTable, GEPIndices);
1558 if (llvm::GlobalValue::isWeakForLinker(VFTableLinkage)) {
1559 VFTableLinkage = llvm::GlobalValue::ExternalLinkage;
1561 C->setSelectionKind(llvm::Comdat::Largest);
1563 VFTable = llvm::GlobalAlias::create(
1564 cast<llvm::SequentialType>(VTableGEP->getType())->getElementType(),
1565 /*AddressSpace=*/0, VFTableLinkage, VFTableName.str(), VTableGEP,
1567 VFTable->setUnnamedAddr(true);
1569 // We don't need a GlobalAlias to be a symbol for the VTable if we won't
1570 // be referencing any RTTI data.
1571 // The GlobalVariable will end up being an appropriate definition of the
1576 VTable->setComdat(C);
1578 if (RD->hasAttr<DLLImportAttr>())
1579 VFTable->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass);
1580 else if (RD->hasAttr<DLLExportAttr>())
1581 VFTable->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
1583 VFTablesMap[ID] = VFTable;
1587 llvm::Value *MicrosoftCXXABI::getVirtualFunctionPointer(CodeGenFunction &CGF,
1591 GD = GD.getCanonicalDecl();
1592 CGBuilderTy &Builder = CGF.Builder;
1594 Ty = Ty->getPointerTo()->getPointerTo();
1596 adjustThisArgumentForVirtualFunctionCall(CGF, GD, This, true);
1597 llvm::Value *VTable = CGF.GetVTablePtr(VPtr, Ty);
1599 MicrosoftVTableContext::MethodVFTableLocation ML =
1600 CGM.getMicrosoftVTableContext().getMethodVFTableLocation(GD);
1601 llvm::Value *VFuncPtr =
1602 Builder.CreateConstInBoundsGEP1_64(VTable, ML.Index, "vfn");
1603 return Builder.CreateLoad(VFuncPtr);
1606 llvm::Value *MicrosoftCXXABI::EmitVirtualDestructorCall(
1607 CodeGenFunction &CGF, const CXXDestructorDecl *Dtor, CXXDtorType DtorType,
1608 llvm::Value *This, const CXXMemberCallExpr *CE) {
1609 assert(CE == nullptr || CE->arg_begin() == CE->arg_end());
1610 assert(DtorType == Dtor_Deleting || DtorType == Dtor_Complete);
1612 // We have only one destructor in the vftable but can get both behaviors
1613 // by passing an implicit int parameter.
1614 GlobalDecl GD(Dtor, Dtor_Deleting);
1615 const CGFunctionInfo *FInfo = &CGM.getTypes().arrangeCXXStructorDeclaration(
1616 Dtor, StructorType::Deleting);
1617 llvm::Type *Ty = CGF.CGM.getTypes().GetFunctionType(*FInfo);
1618 llvm::Value *Callee = getVirtualFunctionPointer(CGF, GD, This, Ty);
1620 ASTContext &Context = getContext();
1621 llvm::Value *ImplicitParam = llvm::ConstantInt::get(
1622 llvm::IntegerType::getInt32Ty(CGF.getLLVMContext()),
1623 DtorType == Dtor_Deleting);
1625 This = adjustThisArgumentForVirtualFunctionCall(CGF, GD, This, true);
1626 RValue RV = CGF.EmitCXXStructorCall(Dtor, Callee, ReturnValueSlot(), This,
1627 ImplicitParam, Context.IntTy, CE,
1628 StructorType::Deleting);
1629 return RV.getScalarVal();
1632 const VBTableGlobals &
1633 MicrosoftCXXABI::enumerateVBTables(const CXXRecordDecl *RD) {
1634 // At this layer, we can key the cache off of a single class, which is much
1635 // easier than caching each vbtable individually.
1636 llvm::DenseMap<const CXXRecordDecl*, VBTableGlobals>::iterator Entry;
1638 std::tie(Entry, Added) =
1639 VBTablesMap.insert(std::make_pair(RD, VBTableGlobals()));
1640 VBTableGlobals &VBGlobals = Entry->second;
1644 MicrosoftVTableContext &Context = CGM.getMicrosoftVTableContext();
1645 VBGlobals.VBTables = &Context.enumerateVBTables(RD);
1647 // Cache the globals for all vbtables so we don't have to recompute the
1649 llvm::GlobalVariable::LinkageTypes Linkage = CGM.getVTableLinkage(RD);
1650 for (VPtrInfoVector::const_iterator I = VBGlobals.VBTables->begin(),
1651 E = VBGlobals.VBTables->end();
1653 VBGlobals.Globals.push_back(getAddrOfVBTable(**I, RD, Linkage));
1659 llvm::Function *MicrosoftCXXABI::EmitVirtualMemPtrThunk(
1660 const CXXMethodDecl *MD,
1661 const MicrosoftVTableContext::MethodVFTableLocation &ML) {
1662 assert(!isa<CXXConstructorDecl>(MD) && !isa<CXXDestructorDecl>(MD) &&
1663 "can't form pointers to ctors or virtual dtors");
1665 // Calculate the mangled name.
1666 SmallString<256> ThunkName;
1667 llvm::raw_svector_ostream Out(ThunkName);
1668 getMangleContext().mangleVirtualMemPtrThunk(MD, Out);
1671 // If the thunk has been generated previously, just return it.
1672 if (llvm::GlobalValue *GV = CGM.getModule().getNamedValue(ThunkName))
1673 return cast<llvm::Function>(GV);
1675 // Create the llvm::Function.
1676 const CGFunctionInfo &FnInfo = CGM.getTypes().arrangeMSMemberPointerThunk(MD);
1677 llvm::FunctionType *ThunkTy = CGM.getTypes().GetFunctionType(FnInfo);
1678 llvm::Function *ThunkFn =
1679 llvm::Function::Create(ThunkTy, llvm::Function::ExternalLinkage,
1680 ThunkName.str(), &CGM.getModule());
1681 assert(ThunkFn->getName() == ThunkName && "name was uniqued!");
1683 ThunkFn->setLinkage(MD->isExternallyVisible()
1684 ? llvm::GlobalValue::LinkOnceODRLinkage
1685 : llvm::GlobalValue::InternalLinkage);
1686 if (MD->isExternallyVisible())
1687 ThunkFn->setComdat(CGM.getModule().getOrInsertComdat(ThunkFn->getName()));
1689 CGM.SetLLVMFunctionAttributes(MD, FnInfo, ThunkFn);
1690 CGM.SetLLVMFunctionAttributesForDefinition(MD, ThunkFn);
1692 // Add the "thunk" attribute so that LLVM knows that the return type is
1693 // meaningless. These thunks can be used to call functions with differing
1694 // return types, and the caller is required to cast the prototype
1695 // appropriately to extract the correct value.
1696 ThunkFn->addFnAttr("thunk");
1698 // These thunks can be compared, so they are not unnamed.
1699 ThunkFn->setUnnamedAddr(false);
1702 CodeGenFunction CGF(CGM);
1703 CGF.CurGD = GlobalDecl(MD);
1704 CGF.CurFuncIsThunk = true;
1706 // Build FunctionArgs, but only include the implicit 'this' parameter
1708 FunctionArgList FunctionArgs;
1709 buildThisParam(CGF, FunctionArgs);
1711 // Start defining the function.
1712 CGF.StartFunction(GlobalDecl(), FnInfo.getReturnType(), ThunkFn, FnInfo,
1713 FunctionArgs, MD->getLocation(), SourceLocation());
1716 // Load the vfptr and then callee from the vftable. The callee should have
1717 // adjusted 'this' so that the vfptr is at offset zero.
1718 llvm::Value *VTable = CGF.GetVTablePtr(
1719 getThisValue(CGF), ThunkTy->getPointerTo()->getPointerTo());
1720 llvm::Value *VFuncPtr =
1721 CGF.Builder.CreateConstInBoundsGEP1_64(VTable, ML.Index, "vfn");
1722 llvm::Value *Callee = CGF.Builder.CreateLoad(VFuncPtr);
1724 CGF.EmitMustTailThunk(MD, getThisValue(CGF), Callee);
1729 void MicrosoftCXXABI::emitVirtualInheritanceTables(const CXXRecordDecl *RD) {
1730 const VBTableGlobals &VBGlobals = enumerateVBTables(RD);
1731 for (unsigned I = 0, E = VBGlobals.VBTables->size(); I != E; ++I) {
1732 const VPtrInfo *VBT = (*VBGlobals.VBTables)[I];
1733 llvm::GlobalVariable *GV = VBGlobals.Globals[I];
1734 if (GV->isDeclaration())
1735 emitVBTableDefinition(*VBT, RD, GV);
1739 llvm::GlobalVariable *
1740 MicrosoftCXXABI::getAddrOfVBTable(const VPtrInfo &VBT, const CXXRecordDecl *RD,
1741 llvm::GlobalVariable::LinkageTypes Linkage) {
1742 SmallString<256> OutName;
1743 llvm::raw_svector_ostream Out(OutName);
1744 getMangleContext().mangleCXXVBTable(RD, VBT.MangledPath, Out);
1746 StringRef Name = OutName.str();
1748 llvm::ArrayType *VBTableType =
1749 llvm::ArrayType::get(CGM.IntTy, 1 + VBT.ReusingBase->getNumVBases());
1751 assert(!CGM.getModule().getNamedGlobal(Name) &&
1752 "vbtable with this name already exists: mangling bug?");
1753 llvm::GlobalVariable *GV =
1754 CGM.CreateOrReplaceCXXRuntimeVariable(Name, VBTableType, Linkage);
1755 GV->setUnnamedAddr(true);
1757 if (RD->hasAttr<DLLImportAttr>())
1758 GV->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass);
1759 else if (RD->hasAttr<DLLExportAttr>())
1760 GV->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
1762 if (!GV->hasExternalLinkage())
1763 emitVBTableDefinition(VBT, RD, GV);
1768 void MicrosoftCXXABI::emitVBTableDefinition(const VPtrInfo &VBT,
1769 const CXXRecordDecl *RD,
1770 llvm::GlobalVariable *GV) const {
1771 const CXXRecordDecl *ReusingBase = VBT.ReusingBase;
1773 assert(RD->getNumVBases() && ReusingBase->getNumVBases() &&
1774 "should only emit vbtables for classes with vbtables");
1776 const ASTRecordLayout &BaseLayout =
1777 getContext().getASTRecordLayout(VBT.BaseWithVPtr);
1778 const ASTRecordLayout &DerivedLayout = getContext().getASTRecordLayout(RD);
1780 SmallVector<llvm::Constant *, 4> Offsets(1 + ReusingBase->getNumVBases(),
1783 // The offset from ReusingBase's vbptr to itself always leads.
1784 CharUnits VBPtrOffset = BaseLayout.getVBPtrOffset();
1785 Offsets[0] = llvm::ConstantInt::get(CGM.IntTy, -VBPtrOffset.getQuantity());
1787 MicrosoftVTableContext &Context = CGM.getMicrosoftVTableContext();
1788 for (const auto &I : ReusingBase->vbases()) {
1789 const CXXRecordDecl *VBase = I.getType()->getAsCXXRecordDecl();
1790 CharUnits Offset = DerivedLayout.getVBaseClassOffset(VBase);
1791 assert(!Offset.isNegative());
1793 // Make it relative to the subobject vbptr.
1794 CharUnits CompleteVBPtrOffset = VBT.NonVirtualOffset + VBPtrOffset;
1795 if (VBT.getVBaseWithVPtr())
1796 CompleteVBPtrOffset +=
1797 DerivedLayout.getVBaseClassOffset(VBT.getVBaseWithVPtr());
1798 Offset -= CompleteVBPtrOffset;
1800 unsigned VBIndex = Context.getVBTableIndex(ReusingBase, VBase);
1801 assert(Offsets[VBIndex] == nullptr && "The same vbindex seen twice?");
1802 Offsets[VBIndex] = llvm::ConstantInt::get(CGM.IntTy, Offset.getQuantity());
1805 assert(Offsets.size() ==
1806 cast<llvm::ArrayType>(cast<llvm::PointerType>(GV->getType())
1807 ->getElementType())->getNumElements());
1808 llvm::ArrayType *VBTableType =
1809 llvm::ArrayType::get(CGM.IntTy, Offsets.size());
1810 llvm::Constant *Init = llvm::ConstantArray::get(VBTableType, Offsets);
1811 GV->setInitializer(Init);
1814 llvm::Value *MicrosoftCXXABI::performThisAdjustment(CodeGenFunction &CGF,
1816 const ThisAdjustment &TA) {
1820 llvm::Value *V = CGF.Builder.CreateBitCast(This, CGF.Int8PtrTy);
1822 if (!TA.Virtual.isEmpty()) {
1823 assert(TA.Virtual.Microsoft.VtordispOffset < 0);
1824 // Adjust the this argument based on the vtordisp value.
1825 llvm::Value *VtorDispPtr =
1826 CGF.Builder.CreateConstGEP1_32(V, TA.Virtual.Microsoft.VtordispOffset);
1828 CGF.Builder.CreateBitCast(VtorDispPtr, CGF.Int32Ty->getPointerTo());
1829 llvm::Value *VtorDisp = CGF.Builder.CreateLoad(VtorDispPtr, "vtordisp");
1830 V = CGF.Builder.CreateGEP(V, CGF.Builder.CreateNeg(VtorDisp));
1832 if (TA.Virtual.Microsoft.VBPtrOffset) {
1833 // If the final overrider is defined in a virtual base other than the one
1834 // that holds the vfptr, we have to use a vtordispex thunk which looks up
1835 // the vbtable of the derived class.
1836 assert(TA.Virtual.Microsoft.VBPtrOffset > 0);
1837 assert(TA.Virtual.Microsoft.VBOffsetOffset >= 0);
1839 llvm::Value *VBaseOffset =
1840 GetVBaseOffsetFromVBPtr(CGF, V, -TA.Virtual.Microsoft.VBPtrOffset,
1841 TA.Virtual.Microsoft.VBOffsetOffset, &VBPtr);
1842 V = CGF.Builder.CreateInBoundsGEP(VBPtr, VBaseOffset);
1846 if (TA.NonVirtual) {
1847 // Non-virtual adjustment might result in a pointer outside the allocated
1848 // object, e.g. if the final overrider class is laid out after the virtual
1849 // base that declares a method in the most derived class.
1850 V = CGF.Builder.CreateConstGEP1_32(V, TA.NonVirtual);
1853 // Don't need to bitcast back, the call CodeGen will handle this.
1858 MicrosoftCXXABI::performReturnAdjustment(CodeGenFunction &CGF, llvm::Value *Ret,
1859 const ReturnAdjustment &RA) {
1863 llvm::Value *V = CGF.Builder.CreateBitCast(Ret, CGF.Int8PtrTy);
1865 if (RA.Virtual.Microsoft.VBIndex) {
1866 assert(RA.Virtual.Microsoft.VBIndex > 0);
1867 const ASTContext &Context = getContext();
1868 int32_t IntSize = Context.getTypeSizeInChars(Context.IntTy).getQuantity();
1870 llvm::Value *VBaseOffset =
1871 GetVBaseOffsetFromVBPtr(CGF, V, RA.Virtual.Microsoft.VBPtrOffset,
1872 IntSize * RA.Virtual.Microsoft.VBIndex, &VBPtr);
1873 V = CGF.Builder.CreateInBoundsGEP(VBPtr, VBaseOffset);
1877 V = CGF.Builder.CreateConstInBoundsGEP1_32(CGF.Int8Ty, V, RA.NonVirtual);
1879 // Cast back to the original type.
1880 return CGF.Builder.CreateBitCast(V, Ret->getType());
1883 bool MicrosoftCXXABI::requiresArrayCookie(const CXXDeleteExpr *expr,
1884 QualType elementType) {
1885 // Microsoft seems to completely ignore the possibility of a
1886 // two-argument usual deallocation function.
1887 return elementType.isDestructedType();
1890 bool MicrosoftCXXABI::requiresArrayCookie(const CXXNewExpr *expr) {
1891 // Microsoft seems to completely ignore the possibility of a
1892 // two-argument usual deallocation function.
1893 return expr->getAllocatedType().isDestructedType();
1896 CharUnits MicrosoftCXXABI::getArrayCookieSizeImpl(QualType type) {
1897 // The array cookie is always a size_t; we then pad that out to the
1898 // alignment of the element type.
1899 ASTContext &Ctx = getContext();
1900 return std::max(Ctx.getTypeSizeInChars(Ctx.getSizeType()),
1901 Ctx.getTypeAlignInChars(type));
1904 llvm::Value *MicrosoftCXXABI::readArrayCookieImpl(CodeGenFunction &CGF,
1905 llvm::Value *allocPtr,
1906 CharUnits cookieSize) {
1907 unsigned AS = allocPtr->getType()->getPointerAddressSpace();
1908 llvm::Value *numElementsPtr =
1909 CGF.Builder.CreateBitCast(allocPtr, CGF.SizeTy->getPointerTo(AS));
1910 return CGF.Builder.CreateLoad(numElementsPtr);
1913 llvm::Value* MicrosoftCXXABI::InitializeArrayCookie(CodeGenFunction &CGF,
1914 llvm::Value *newPtr,
1915 llvm::Value *numElements,
1916 const CXXNewExpr *expr,
1917 QualType elementType) {
1918 assert(requiresArrayCookie(expr));
1920 // The size of the cookie.
1921 CharUnits cookieSize = getArrayCookieSizeImpl(elementType);
1923 // Compute an offset to the cookie.
1924 llvm::Value *cookiePtr = newPtr;
1926 // Write the number of elements into the appropriate slot.
1927 unsigned AS = newPtr->getType()->getPointerAddressSpace();
1928 llvm::Value *numElementsPtr
1929 = CGF.Builder.CreateBitCast(cookiePtr, CGF.SizeTy->getPointerTo(AS));
1930 CGF.Builder.CreateStore(numElements, numElementsPtr);
1932 // Finally, compute a pointer to the actual data buffer by skipping
1933 // over the cookie completely.
1934 return CGF.Builder.CreateConstInBoundsGEP1_64(newPtr,
1935 cookieSize.getQuantity());
1938 static void emitGlobalDtorWithTLRegDtor(CodeGenFunction &CGF, const VarDecl &VD,
1939 llvm::Constant *Dtor,
1940 llvm::Constant *Addr) {
1941 // Create a function which calls the destructor.
1942 llvm::Constant *DtorStub = CGF.createAtExitStub(VD, Dtor, Addr);
1944 // extern "C" int __tlregdtor(void (*f)(void));
1945 llvm::FunctionType *TLRegDtorTy = llvm::FunctionType::get(
1946 CGF.IntTy, DtorStub->getType(), /*IsVarArg=*/false);
1948 llvm::Constant *TLRegDtor =
1949 CGF.CGM.CreateRuntimeFunction(TLRegDtorTy, "__tlregdtor");
1950 if (llvm::Function *TLRegDtorFn = dyn_cast<llvm::Function>(TLRegDtor))
1951 TLRegDtorFn->setDoesNotThrow();
1953 CGF.EmitNounwindRuntimeCall(TLRegDtor, DtorStub);
1956 void MicrosoftCXXABI::registerGlobalDtor(CodeGenFunction &CGF, const VarDecl &D,
1957 llvm::Constant *Dtor,
1958 llvm::Constant *Addr) {
1960 return emitGlobalDtorWithTLRegDtor(CGF, D, Dtor, Addr);
1962 // The default behavior is to use atexit.
1963 CGF.registerGlobalDtorWithAtExit(D, Dtor, Addr);
1966 void MicrosoftCXXABI::EmitThreadLocalInitFuncs(
1968 ArrayRef<std::pair<const VarDecl *, llvm::GlobalVariable *>>
1970 ArrayRef<llvm::Function *> CXXThreadLocalInits,
1971 ArrayRef<llvm::GlobalVariable *> CXXThreadLocalInitVars) {
1972 // This will create a GV in the .CRT$XDU section. It will point to our
1973 // initialization function. The CRT will call all of these function
1974 // pointers at start-up time and, eventually, at thread-creation time.
1975 auto AddToXDU = [&CGM](llvm::Function *InitFunc) {
1976 llvm::GlobalVariable *InitFuncPtr = new llvm::GlobalVariable(
1977 CGM.getModule(), InitFunc->getType(), /*IsConstant=*/true,
1978 llvm::GlobalVariable::InternalLinkage, InitFunc,
1979 Twine(InitFunc->getName(), "$initializer$"));
1980 InitFuncPtr->setSection(".CRT$XDU");
1981 // This variable has discardable linkage, we have to add it to @llvm.used to
1982 // ensure it won't get discarded.
1983 CGM.addUsedGlobal(InitFuncPtr);
1987 std::vector<llvm::Function *> NonComdatInits;
1988 for (size_t I = 0, E = CXXThreadLocalInitVars.size(); I != E; ++I) {
1989 llvm::GlobalVariable *GV = CXXThreadLocalInitVars[I];
1990 llvm::Function *F = CXXThreadLocalInits[I];
1992 // If the GV is already in a comdat group, then we have to join it.
1993 if (llvm::Comdat *C = GV->getComdat())
1994 AddToXDU(F)->setComdat(C);
1996 NonComdatInits.push_back(F);
1999 if (!NonComdatInits.empty()) {
2000 llvm::FunctionType *FTy =
2001 llvm::FunctionType::get(CGM.VoidTy, /*isVarArg=*/false);
2002 llvm::Function *InitFunc = CGM.CreateGlobalInitOrDestructFunction(
2003 FTy, "__tls_init", SourceLocation(),
2005 CodeGenFunction(CGM).GenerateCXXGlobalInitFunc(InitFunc, NonComdatInits);
2011 LValue MicrosoftCXXABI::EmitThreadLocalVarDeclLValue(CodeGenFunction &CGF,
2013 QualType LValType) {
2014 CGF.CGM.ErrorUnsupported(VD, "thread wrappers");
2018 void MicrosoftCXXABI::EmitGuardedInit(CodeGenFunction &CGF, const VarDecl &D,
2019 llvm::GlobalVariable *GV,
2021 // MSVC only uses guards for static locals.
2022 if (!D.isStaticLocal()) {
2023 assert(GV->hasWeakLinkage() || GV->hasLinkOnceLinkage());
2024 // GlobalOpt is allowed to discard the initializer, so use linkonce_odr.
2025 llvm::Function *F = CGF.CurFn;
2026 F->setLinkage(llvm::GlobalValue::LinkOnceODRLinkage);
2027 F->setComdat(CGM.getModule().getOrInsertComdat(F->getName()));
2028 CGF.EmitCXXGlobalVarDeclInit(D, GV, PerformInit);
2032 // MSVC always uses an i32 bitfield to guard initialization, which is *not*
2033 // threadsafe. Since the user may be linking in inline functions compiled by
2034 // cl.exe, there's no reason to provide a false sense of security by using
2035 // critical sections here.
2038 CGM.ErrorUnsupported(&D, "dynamic TLS initialization");
2040 CGBuilderTy &Builder = CGF.Builder;
2041 llvm::IntegerType *GuardTy = CGF.Int32Ty;
2042 llvm::ConstantInt *Zero = llvm::ConstantInt::get(GuardTy, 0);
2044 // Get the guard variable for this function if we have one already.
2045 GuardInfo *GI = &GuardVariableMap[D.getDeclContext()];
2048 if (D.isStaticLocal() && D.isExternallyVisible()) {
2049 // Externally visible variables have to be numbered in Sema to properly
2050 // handle unreachable VarDecls.
2051 BitIndex = getContext().getStaticLocalNumber(&D);
2052 assert(BitIndex > 0);
2055 // Non-externally visible variables are numbered here in CodeGen.
2056 BitIndex = GI->BitIndex++;
2059 if (BitIndex >= 32) {
2060 if (D.isExternallyVisible())
2061 ErrorUnsupportedABI(CGF, "more than 32 guarded initializations");
2063 GI->Guard = nullptr;
2066 // Lazily create the i32 bitfield for this function.
2068 // Mangle the name for the guard.
2069 SmallString<256> GuardName;
2071 llvm::raw_svector_ostream Out(GuardName);
2072 getMangleContext().mangleStaticGuardVariable(&D, Out);
2076 // Create the guard variable with a zero-initializer. Just absorb linkage,
2077 // visibility and dll storage class from the guarded variable.
2079 new llvm::GlobalVariable(CGM.getModule(), GuardTy, false,
2080 GV->getLinkage(), Zero, GuardName.str());
2081 GI->Guard->setVisibility(GV->getVisibility());
2082 GI->Guard->setDLLStorageClass(GV->getDLLStorageClass());
2083 if (GI->Guard->isWeakForLinker())
2084 GI->Guard->setComdat(
2085 CGM.getModule().getOrInsertComdat(GI->Guard->getName()));
2087 assert(GI->Guard->getLinkage() == GV->getLinkage() &&
2088 "static local from the same function had different linkage");
2091 // Pseudo code for the test:
2092 // if (!(GuardVar & MyGuardBit)) {
2093 // GuardVar |= MyGuardBit;
2094 // ... initialize the object ...;
2097 // Test our bit from the guard variable.
2098 llvm::ConstantInt *Bit = llvm::ConstantInt::get(GuardTy, 1U << BitIndex);
2099 llvm::LoadInst *LI = Builder.CreateLoad(GI->Guard);
2100 llvm::Value *IsInitialized =
2101 Builder.CreateICmpNE(Builder.CreateAnd(LI, Bit), Zero);
2102 llvm::BasicBlock *InitBlock = CGF.createBasicBlock("init");
2103 llvm::BasicBlock *EndBlock = CGF.createBasicBlock("init.end");
2104 Builder.CreateCondBr(IsInitialized, EndBlock, InitBlock);
2106 // Set our bit in the guard variable and emit the initializer and add a global
2107 // destructor if appropriate.
2108 CGF.EmitBlock(InitBlock);
2109 Builder.CreateStore(Builder.CreateOr(LI, Bit), GI->Guard);
2110 CGF.EmitCXXGlobalVarDeclInit(D, GV, PerformInit);
2111 Builder.CreateBr(EndBlock);
2114 CGF.EmitBlock(EndBlock);
2117 bool MicrosoftCXXABI::isZeroInitializable(const MemberPointerType *MPT) {
2118 // Null-ness for function memptrs only depends on the first field, which is
2119 // the function pointer. The rest don't matter, so we can zero initialize.
2120 if (MPT->isMemberFunctionPointer())
2123 // The virtual base adjustment field is always -1 for null, so if we have one
2124 // we can't zero initialize. The field offset is sometimes also -1 if 0 is a
2125 // valid field offset.
2126 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2127 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2128 return (!MSInheritanceAttr::hasVBTableOffsetField(Inheritance) &&
2129 RD->nullFieldOffsetIsZero());
2133 MicrosoftCXXABI::ConvertMemberPointerType(const MemberPointerType *MPT) {
2134 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2135 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2136 llvm::SmallVector<llvm::Type *, 4> fields;
2137 if (MPT->isMemberFunctionPointer())
2138 fields.push_back(CGM.VoidPtrTy); // FunctionPointerOrVirtualThunk
2140 fields.push_back(CGM.IntTy); // FieldOffset
2142 if (MSInheritanceAttr::hasNVOffsetField(MPT->isMemberFunctionPointer(),
2144 fields.push_back(CGM.IntTy);
2145 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance))
2146 fields.push_back(CGM.IntTy);
2147 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2148 fields.push_back(CGM.IntTy); // VirtualBaseAdjustmentOffset
2150 if (fields.size() == 1)
2152 return llvm::StructType::get(CGM.getLLVMContext(), fields);
2155 void MicrosoftCXXABI::
2156 GetNullMemberPointerFields(const MemberPointerType *MPT,
2157 llvm::SmallVectorImpl<llvm::Constant *> &fields) {
2158 assert(fields.empty());
2159 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2160 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2161 if (MPT->isMemberFunctionPointer()) {
2162 // FunctionPointerOrVirtualThunk
2163 fields.push_back(llvm::Constant::getNullValue(CGM.VoidPtrTy));
2165 if (RD->nullFieldOffsetIsZero())
2166 fields.push_back(getZeroInt()); // FieldOffset
2168 fields.push_back(getAllOnesInt()); // FieldOffset
2171 if (MSInheritanceAttr::hasNVOffsetField(MPT->isMemberFunctionPointer(),
2173 fields.push_back(getZeroInt());
2174 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance))
2175 fields.push_back(getZeroInt());
2176 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2177 fields.push_back(getAllOnesInt());
2181 MicrosoftCXXABI::EmitNullMemberPointer(const MemberPointerType *MPT) {
2182 llvm::SmallVector<llvm::Constant *, 4> fields;
2183 GetNullMemberPointerFields(MPT, fields);
2184 if (fields.size() == 1)
2186 llvm::Constant *Res = llvm::ConstantStruct::getAnon(fields);
2187 assert(Res->getType() == ConvertMemberPointerType(MPT));
2192 MicrosoftCXXABI::EmitFullMemberPointer(llvm::Constant *FirstField,
2193 bool IsMemberFunction,
2194 const CXXRecordDecl *RD,
2195 CharUnits NonVirtualBaseAdjustment)
2197 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2199 // Single inheritance class member pointer are represented as scalars instead
2201 if (MSInheritanceAttr::hasOnlyOneField(IsMemberFunction, Inheritance))
2204 llvm::SmallVector<llvm::Constant *, 4> fields;
2205 fields.push_back(FirstField);
2207 if (MSInheritanceAttr::hasNVOffsetField(IsMemberFunction, Inheritance))
2208 fields.push_back(llvm::ConstantInt::get(
2209 CGM.IntTy, NonVirtualBaseAdjustment.getQuantity()));
2211 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance)) {
2212 CharUnits Offs = CharUnits::Zero();
2213 if (RD->getNumVBases())
2214 Offs = getContext().getASTRecordLayout(RD).getVBPtrOffset();
2215 fields.push_back(llvm::ConstantInt::get(CGM.IntTy, Offs.getQuantity()));
2218 // The rest of the fields are adjusted by conversions to a more derived class.
2219 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2220 fields.push_back(getZeroInt());
2222 return llvm::ConstantStruct::getAnon(fields);
2226 MicrosoftCXXABI::EmitMemberDataPointer(const MemberPointerType *MPT,
2228 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2229 llvm::Constant *FirstField =
2230 llvm::ConstantInt::get(CGM.IntTy, offset.getQuantity());
2231 return EmitFullMemberPointer(FirstField, /*IsMemberFunction=*/false, RD,
2235 llvm::Constant *MicrosoftCXXABI::EmitMemberPointer(const CXXMethodDecl *MD) {
2236 return BuildMemberPointer(MD->getParent(), MD, CharUnits::Zero());
2239 llvm::Constant *MicrosoftCXXABI::EmitMemberPointer(const APValue &MP,
2241 const MemberPointerType *MPT = MPType->castAs<MemberPointerType>();
2242 const ValueDecl *MPD = MP.getMemberPointerDecl();
2244 return EmitNullMemberPointer(MPT);
2246 CharUnits ThisAdjustment = getMemberPointerPathAdjustment(MP);
2248 // FIXME PR15713: Support virtual inheritance paths.
2250 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(MPD))
2251 return BuildMemberPointer(MPT->getMostRecentCXXRecordDecl(), MD,
2254 CharUnits FieldOffset =
2255 getContext().toCharUnitsFromBits(getContext().getFieldOffset(MPD));
2256 return EmitMemberDataPointer(MPT, ThisAdjustment + FieldOffset);
2260 MicrosoftCXXABI::BuildMemberPointer(const CXXRecordDecl *RD,
2261 const CXXMethodDecl *MD,
2262 CharUnits NonVirtualBaseAdjustment) {
2263 assert(MD->isInstance() && "Member function must not be static!");
2264 MD = MD->getCanonicalDecl();
2265 RD = RD->getMostRecentDecl();
2266 CodeGenTypes &Types = CGM.getTypes();
2268 llvm::Constant *FirstField;
2269 const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>();
2270 if (!MD->isVirtual()) {
2272 // Check whether the function has a computable LLVM signature.
2273 if (Types.isFuncTypeConvertible(FPT)) {
2274 // The function has a computable LLVM signature; use the correct type.
2275 Ty = Types.GetFunctionType(Types.arrangeCXXMethodDeclaration(MD));
2277 // Use an arbitrary non-function type to tell GetAddrOfFunction that the
2278 // function type is incomplete.
2281 FirstField = CGM.GetAddrOfFunction(MD, Ty);
2282 FirstField = llvm::ConstantExpr::getBitCast(FirstField, CGM.VoidPtrTy);
2284 MicrosoftVTableContext::MethodVFTableLocation ML =
2285 CGM.getMicrosoftVTableContext().getMethodVFTableLocation(MD);
2286 if (!CGM.getTypes().isFuncTypeConvertible(
2287 MD->getType()->castAs<FunctionType>())) {
2288 CGM.ErrorUnsupported(MD, "pointer to virtual member function with "
2289 "incomplete return or parameter type");
2290 FirstField = llvm::Constant::getNullValue(CGM.VoidPtrTy);
2291 } else if (FPT->getCallConv() == CC_X86FastCall) {
2292 CGM.ErrorUnsupported(MD, "pointer to fastcall virtual member function");
2293 FirstField = llvm::Constant::getNullValue(CGM.VoidPtrTy);
2294 } else if (ML.VBase) {
2295 CGM.ErrorUnsupported(MD, "pointer to virtual member function overriding "
2296 "member function in virtual base class");
2297 FirstField = llvm::Constant::getNullValue(CGM.VoidPtrTy);
2299 llvm::Function *Thunk = EmitVirtualMemPtrThunk(MD, ML);
2300 FirstField = llvm::ConstantExpr::getBitCast(Thunk, CGM.VoidPtrTy);
2301 // Include the vfptr adjustment if the method is in a non-primary vftable.
2302 NonVirtualBaseAdjustment += ML.VFPtrOffset;
2306 // The rest of the fields are common with data member pointers.
2307 return EmitFullMemberPointer(FirstField, /*IsMemberFunction=*/true, RD,
2308 NonVirtualBaseAdjustment);
2311 /// Member pointers are the same if they're either bitwise identical *or* both
2312 /// null. Null-ness for function members is determined by the first field,
2313 /// while for data member pointers we must compare all fields.
2315 MicrosoftCXXABI::EmitMemberPointerComparison(CodeGenFunction &CGF,
2318 const MemberPointerType *MPT,
2320 CGBuilderTy &Builder = CGF.Builder;
2322 // Handle != comparisons by switching the sense of all boolean operations.
2323 llvm::ICmpInst::Predicate Eq;
2324 llvm::Instruction::BinaryOps And, Or;
2326 Eq = llvm::ICmpInst::ICMP_NE;
2327 And = llvm::Instruction::Or;
2328 Or = llvm::Instruction::And;
2330 Eq = llvm::ICmpInst::ICMP_EQ;
2331 And = llvm::Instruction::And;
2332 Or = llvm::Instruction::Or;
2335 // If this is a single field member pointer (single inheritance), this is a
2337 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2338 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2339 if (MSInheritanceAttr::hasOnlyOneField(MPT->isMemberFunctionPointer(),
2341 return Builder.CreateICmp(Eq, L, R);
2343 // Compare the first field.
2344 llvm::Value *L0 = Builder.CreateExtractValue(L, 0, "lhs.0");
2345 llvm::Value *R0 = Builder.CreateExtractValue(R, 0, "rhs.0");
2346 llvm::Value *Cmp0 = Builder.CreateICmp(Eq, L0, R0, "memptr.cmp.first");
2348 // Compare everything other than the first field.
2349 llvm::Value *Res = nullptr;
2350 llvm::StructType *LType = cast<llvm::StructType>(L->getType());
2351 for (unsigned I = 1, E = LType->getNumElements(); I != E; ++I) {
2352 llvm::Value *LF = Builder.CreateExtractValue(L, I);
2353 llvm::Value *RF = Builder.CreateExtractValue(R, I);
2354 llvm::Value *Cmp = Builder.CreateICmp(Eq, LF, RF, "memptr.cmp.rest");
2356 Res = Builder.CreateBinOp(And, Res, Cmp);
2361 // Check if the first field is 0 if this is a function pointer.
2362 if (MPT->isMemberFunctionPointer()) {
2363 // (l1 == r1 && ...) || l0 == 0
2364 llvm::Value *Zero = llvm::Constant::getNullValue(L0->getType());
2365 llvm::Value *IsZero = Builder.CreateICmp(Eq, L0, Zero, "memptr.cmp.iszero");
2366 Res = Builder.CreateBinOp(Or, Res, IsZero);
2369 // Combine the comparison of the first field, which must always be true for
2370 // this comparison to succeeed.
2371 return Builder.CreateBinOp(And, Res, Cmp0, "memptr.cmp");
2375 MicrosoftCXXABI::EmitMemberPointerIsNotNull(CodeGenFunction &CGF,
2376 llvm::Value *MemPtr,
2377 const MemberPointerType *MPT) {
2378 CGBuilderTy &Builder = CGF.Builder;
2379 llvm::SmallVector<llvm::Constant *, 4> fields;
2380 // We only need one field for member functions.
2381 if (MPT->isMemberFunctionPointer())
2382 fields.push_back(llvm::Constant::getNullValue(CGM.VoidPtrTy));
2384 GetNullMemberPointerFields(MPT, fields);
2385 assert(!fields.empty());
2386 llvm::Value *FirstField = MemPtr;
2387 if (MemPtr->getType()->isStructTy())
2388 FirstField = Builder.CreateExtractValue(MemPtr, 0);
2389 llvm::Value *Res = Builder.CreateICmpNE(FirstField, fields[0], "memptr.cmp0");
2391 // For function member pointers, we only need to test the function pointer
2392 // field. The other fields if any can be garbage.
2393 if (MPT->isMemberFunctionPointer())
2396 // Otherwise, emit a series of compares and combine the results.
2397 for (int I = 1, E = fields.size(); I < E; ++I) {
2398 llvm::Value *Field = Builder.CreateExtractValue(MemPtr, I);
2399 llvm::Value *Next = Builder.CreateICmpNE(Field, fields[I], "memptr.cmp");
2400 Res = Builder.CreateOr(Res, Next, "memptr.tobool");
2405 bool MicrosoftCXXABI::MemberPointerConstantIsNull(const MemberPointerType *MPT,
2406 llvm::Constant *Val) {
2407 // Function pointers are null if the pointer in the first field is null.
2408 if (MPT->isMemberFunctionPointer()) {
2409 llvm::Constant *FirstField = Val->getType()->isStructTy() ?
2410 Val->getAggregateElement(0U) : Val;
2411 return FirstField->isNullValue();
2414 // If it's not a function pointer and it's zero initializable, we can easily
2416 if (isZeroInitializable(MPT) && Val->isNullValue())
2419 // Otherwise, break down all the fields for comparison. Hopefully these
2420 // little Constants are reused, while a big null struct might not be.
2421 llvm::SmallVector<llvm::Constant *, 4> Fields;
2422 GetNullMemberPointerFields(MPT, Fields);
2423 if (Fields.size() == 1) {
2424 assert(Val->getType()->isIntegerTy());
2425 return Val == Fields[0];
2429 for (I = 0, E = Fields.size(); I != E; ++I) {
2430 if (Val->getAggregateElement(I) != Fields[I])
2437 MicrosoftCXXABI::GetVBaseOffsetFromVBPtr(CodeGenFunction &CGF,
2439 llvm::Value *VBPtrOffset,
2440 llvm::Value *VBTableOffset,
2441 llvm::Value **VBPtrOut) {
2442 CGBuilderTy &Builder = CGF.Builder;
2443 // Load the vbtable pointer from the vbptr in the instance.
2444 This = Builder.CreateBitCast(This, CGM.Int8PtrTy);
2445 llvm::Value *VBPtr =
2446 Builder.CreateInBoundsGEP(This, VBPtrOffset, "vbptr");
2447 if (VBPtrOut) *VBPtrOut = VBPtr;
2448 VBPtr = Builder.CreateBitCast(VBPtr,
2449 CGM.Int32Ty->getPointerTo(0)->getPointerTo(0));
2450 llvm::Value *VBTable = Builder.CreateLoad(VBPtr, "vbtable");
2452 // Translate from byte offset to table index. It improves analyzability.
2453 llvm::Value *VBTableIndex = Builder.CreateAShr(
2454 VBTableOffset, llvm::ConstantInt::get(VBTableOffset->getType(), 2),
2455 "vbtindex", /*isExact=*/true);
2457 // Load an i32 offset from the vb-table.
2458 llvm::Value *VBaseOffs = Builder.CreateInBoundsGEP(VBTable, VBTableIndex);
2459 VBaseOffs = Builder.CreateBitCast(VBaseOffs, CGM.Int32Ty->getPointerTo(0));
2460 return Builder.CreateLoad(VBaseOffs, "vbase_offs");
2463 // Returns an adjusted base cast to i8*, since we do more address arithmetic on
2465 llvm::Value *MicrosoftCXXABI::AdjustVirtualBase(
2466 CodeGenFunction &CGF, const Expr *E, const CXXRecordDecl *RD,
2467 llvm::Value *Base, llvm::Value *VBTableOffset, llvm::Value *VBPtrOffset) {
2468 CGBuilderTy &Builder = CGF.Builder;
2469 Base = Builder.CreateBitCast(Base, CGM.Int8PtrTy);
2470 llvm::BasicBlock *OriginalBB = nullptr;
2471 llvm::BasicBlock *SkipAdjustBB = nullptr;
2472 llvm::BasicBlock *VBaseAdjustBB = nullptr;
2474 // In the unspecified inheritance model, there might not be a vbtable at all,
2475 // in which case we need to skip the virtual base lookup. If there is a
2476 // vbtable, the first entry is a no-op entry that gives back the original
2477 // base, so look for a virtual base adjustment offset of zero.
2479 OriginalBB = Builder.GetInsertBlock();
2480 VBaseAdjustBB = CGF.createBasicBlock("memptr.vadjust");
2481 SkipAdjustBB = CGF.createBasicBlock("memptr.skip_vadjust");
2482 llvm::Value *IsVirtual =
2483 Builder.CreateICmpNE(VBTableOffset, getZeroInt(),
2485 Builder.CreateCondBr(IsVirtual, VBaseAdjustBB, SkipAdjustBB);
2486 CGF.EmitBlock(VBaseAdjustBB);
2489 // If we weren't given a dynamic vbptr offset, RD should be complete and we'll
2490 // know the vbptr offset.
2492 CharUnits offs = CharUnits::Zero();
2493 if (!RD->hasDefinition()) {
2494 DiagnosticsEngine &Diags = CGF.CGM.getDiags();
2495 unsigned DiagID = Diags.getCustomDiagID(
2496 DiagnosticsEngine::Error,
2497 "member pointer representation requires a "
2498 "complete class type for %0 to perform this expression");
2499 Diags.Report(E->getExprLoc(), DiagID) << RD << E->getSourceRange();
2500 } else if (RD->getNumVBases())
2501 offs = getContext().getASTRecordLayout(RD).getVBPtrOffset();
2502 VBPtrOffset = llvm::ConstantInt::get(CGM.IntTy, offs.getQuantity());
2504 llvm::Value *VBPtr = nullptr;
2505 llvm::Value *VBaseOffs =
2506 GetVBaseOffsetFromVBPtr(CGF, Base, VBPtrOffset, VBTableOffset, &VBPtr);
2507 llvm::Value *AdjustedBase = Builder.CreateInBoundsGEP(VBPtr, VBaseOffs);
2509 // Merge control flow with the case where we didn't have to adjust.
2510 if (VBaseAdjustBB) {
2511 Builder.CreateBr(SkipAdjustBB);
2512 CGF.EmitBlock(SkipAdjustBB);
2513 llvm::PHINode *Phi = Builder.CreatePHI(CGM.Int8PtrTy, 2, "memptr.base");
2514 Phi->addIncoming(Base, OriginalBB);
2515 Phi->addIncoming(AdjustedBase, VBaseAdjustBB);
2518 return AdjustedBase;
2521 llvm::Value *MicrosoftCXXABI::EmitMemberDataPointerAddress(
2522 CodeGenFunction &CGF, const Expr *E, llvm::Value *Base, llvm::Value *MemPtr,
2523 const MemberPointerType *MPT) {
2524 assert(MPT->isMemberDataPointer());
2525 unsigned AS = Base->getType()->getPointerAddressSpace();
2527 CGF.ConvertTypeForMem(MPT->getPointeeType())->getPointerTo(AS);
2528 CGBuilderTy &Builder = CGF.Builder;
2529 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2530 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2532 // Extract the fields we need, regardless of model. We'll apply them if we
2534 llvm::Value *FieldOffset = MemPtr;
2535 llvm::Value *VirtualBaseAdjustmentOffset = nullptr;
2536 llvm::Value *VBPtrOffset = nullptr;
2537 if (MemPtr->getType()->isStructTy()) {
2538 // We need to extract values.
2540 FieldOffset = Builder.CreateExtractValue(MemPtr, I++);
2541 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance))
2542 VBPtrOffset = Builder.CreateExtractValue(MemPtr, I++);
2543 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2544 VirtualBaseAdjustmentOffset = Builder.CreateExtractValue(MemPtr, I++);
2547 if (VirtualBaseAdjustmentOffset) {
2548 Base = AdjustVirtualBase(CGF, E, RD, Base, VirtualBaseAdjustmentOffset,
2553 Base = Builder.CreateBitCast(Base, Builder.getInt8Ty()->getPointerTo(AS));
2555 // Apply the offset, which we assume is non-null.
2557 Builder.CreateInBoundsGEP(Base, FieldOffset, "memptr.offset");
2559 // Cast the address to the appropriate pointer type, adopting the address
2560 // space of the base pointer.
2561 return Builder.CreateBitCast(Addr, PType);
2564 static MSInheritanceAttr::Spelling
2565 getInheritanceFromMemptr(const MemberPointerType *MPT) {
2566 return MPT->getMostRecentCXXRecordDecl()->getMSInheritanceModel();
2570 MicrosoftCXXABI::EmitMemberPointerConversion(CodeGenFunction &CGF,
2573 assert(E->getCastKind() == CK_DerivedToBaseMemberPointer ||
2574 E->getCastKind() == CK_BaseToDerivedMemberPointer ||
2575 E->getCastKind() == CK_ReinterpretMemberPointer);
2577 // Use constant emission if we can.
2578 if (isa<llvm::Constant>(Src))
2579 return EmitMemberPointerConversion(E, cast<llvm::Constant>(Src));
2581 // We may be adding or dropping fields from the member pointer, so we need
2582 // both types and the inheritance models of both records.
2583 const MemberPointerType *SrcTy =
2584 E->getSubExpr()->getType()->castAs<MemberPointerType>();
2585 const MemberPointerType *DstTy = E->getType()->castAs<MemberPointerType>();
2586 bool IsFunc = SrcTy->isMemberFunctionPointer();
2588 // If the classes use the same null representation, reinterpret_cast is a nop.
2589 bool IsReinterpret = E->getCastKind() == CK_ReinterpretMemberPointer;
2590 if (IsReinterpret && IsFunc)
2593 CXXRecordDecl *SrcRD = SrcTy->getMostRecentCXXRecordDecl();
2594 CXXRecordDecl *DstRD = DstTy->getMostRecentCXXRecordDecl();
2595 if (IsReinterpret &&
2596 SrcRD->nullFieldOffsetIsZero() == DstRD->nullFieldOffsetIsZero())
2599 CGBuilderTy &Builder = CGF.Builder;
2601 // Branch past the conversion if Src is null.
2602 llvm::Value *IsNotNull = EmitMemberPointerIsNotNull(CGF, Src, SrcTy);
2603 llvm::Constant *DstNull = EmitNullMemberPointer(DstTy);
2605 // C++ 5.2.10p9: The null member pointer value is converted to the null member
2606 // pointer value of the destination type.
2607 if (IsReinterpret) {
2608 // For reinterpret casts, sema ensures that src and dst are both functions
2609 // or data and have the same size, which means the LLVM types should match.
2610 assert(Src->getType() == DstNull->getType());
2611 return Builder.CreateSelect(IsNotNull, Src, DstNull);
2614 llvm::BasicBlock *OriginalBB = Builder.GetInsertBlock();
2615 llvm::BasicBlock *ConvertBB = CGF.createBasicBlock("memptr.convert");
2616 llvm::BasicBlock *ContinueBB = CGF.createBasicBlock("memptr.converted");
2617 Builder.CreateCondBr(IsNotNull, ConvertBB, ContinueBB);
2618 CGF.EmitBlock(ConvertBB);
2621 llvm::Value *FirstField = Src;
2622 llvm::Value *NonVirtualBaseAdjustment = nullptr;
2623 llvm::Value *VirtualBaseAdjustmentOffset = nullptr;
2624 llvm::Value *VBPtrOffset = nullptr;
2625 MSInheritanceAttr::Spelling SrcInheritance = SrcRD->getMSInheritanceModel();
2626 if (!MSInheritanceAttr::hasOnlyOneField(IsFunc, SrcInheritance)) {
2627 // We need to extract values.
2629 FirstField = Builder.CreateExtractValue(Src, I++);
2630 if (MSInheritanceAttr::hasNVOffsetField(IsFunc, SrcInheritance))
2631 NonVirtualBaseAdjustment = Builder.CreateExtractValue(Src, I++);
2632 if (MSInheritanceAttr::hasVBPtrOffsetField(SrcInheritance))
2633 VBPtrOffset = Builder.CreateExtractValue(Src, I++);
2634 if (MSInheritanceAttr::hasVBTableOffsetField(SrcInheritance))
2635 VirtualBaseAdjustmentOffset = Builder.CreateExtractValue(Src, I++);
2638 // For data pointers, we adjust the field offset directly. For functions, we
2639 // have a separate field.
2640 llvm::Constant *Adj = getMemberPointerAdjustment(E);
2642 Adj = llvm::ConstantExpr::getTruncOrBitCast(Adj, CGM.IntTy);
2643 llvm::Value *&NVAdjustField = IsFunc ? NonVirtualBaseAdjustment : FirstField;
2644 bool isDerivedToBase = (E->getCastKind() == CK_DerivedToBaseMemberPointer);
2645 if (!NVAdjustField) // If this field didn't exist in src, it's zero.
2646 NVAdjustField = getZeroInt();
2647 if (isDerivedToBase)
2648 NVAdjustField = Builder.CreateNSWSub(NVAdjustField, Adj, "adj");
2650 NVAdjustField = Builder.CreateNSWAdd(NVAdjustField, Adj, "adj");
2653 // FIXME PR15713: Support conversions through virtually derived classes.
2655 // Recompose dst from the null struct and the adjusted fields from src.
2656 MSInheritanceAttr::Spelling DstInheritance = DstRD->getMSInheritanceModel();
2658 if (MSInheritanceAttr::hasOnlyOneField(IsFunc, DstInheritance)) {
2661 Dst = llvm::UndefValue::get(DstNull->getType());
2663 Dst = Builder.CreateInsertValue(Dst, FirstField, Idx++);
2664 if (MSInheritanceAttr::hasNVOffsetField(IsFunc, DstInheritance))
2665 Dst = Builder.CreateInsertValue(
2666 Dst, getValueOrZeroInt(NonVirtualBaseAdjustment), Idx++);
2667 if (MSInheritanceAttr::hasVBPtrOffsetField(DstInheritance))
2668 Dst = Builder.CreateInsertValue(
2669 Dst, getValueOrZeroInt(VBPtrOffset), Idx++);
2670 if (MSInheritanceAttr::hasVBTableOffsetField(DstInheritance))
2671 Dst = Builder.CreateInsertValue(
2672 Dst, getValueOrZeroInt(VirtualBaseAdjustmentOffset), Idx++);
2674 Builder.CreateBr(ContinueBB);
2676 // In the continuation, choose between DstNull and Dst.
2677 CGF.EmitBlock(ContinueBB);
2678 llvm::PHINode *Phi = Builder.CreatePHI(DstNull->getType(), 2, "memptr.converted");
2679 Phi->addIncoming(DstNull, OriginalBB);
2680 Phi->addIncoming(Dst, ConvertBB);
2685 MicrosoftCXXABI::EmitMemberPointerConversion(const CastExpr *E,
2686 llvm::Constant *Src) {
2687 const MemberPointerType *SrcTy =
2688 E->getSubExpr()->getType()->castAs<MemberPointerType>();
2689 const MemberPointerType *DstTy = E->getType()->castAs<MemberPointerType>();
2691 // If src is null, emit a new null for dst. We can't return src because dst
2692 // might have a new representation.
2693 if (MemberPointerConstantIsNull(SrcTy, Src))
2694 return EmitNullMemberPointer(DstTy);
2696 // We don't need to do anything for reinterpret_casts of non-null member
2697 // pointers. We should only get here when the two type representations have
2699 if (E->getCastKind() == CK_ReinterpretMemberPointer)
2702 MSInheritanceAttr::Spelling SrcInheritance = getInheritanceFromMemptr(SrcTy);
2703 MSInheritanceAttr::Spelling DstInheritance = getInheritanceFromMemptr(DstTy);
2706 llvm::Constant *FirstField = Src;
2707 llvm::Constant *NonVirtualBaseAdjustment = nullptr;
2708 llvm::Constant *VirtualBaseAdjustmentOffset = nullptr;
2709 llvm::Constant *VBPtrOffset = nullptr;
2710 bool IsFunc = SrcTy->isMemberFunctionPointer();
2711 if (!MSInheritanceAttr::hasOnlyOneField(IsFunc, SrcInheritance)) {
2712 // We need to extract values.
2714 FirstField = Src->getAggregateElement(I++);
2715 if (MSInheritanceAttr::hasNVOffsetField(IsFunc, SrcInheritance))
2716 NonVirtualBaseAdjustment = Src->getAggregateElement(I++);
2717 if (MSInheritanceAttr::hasVBPtrOffsetField(SrcInheritance))
2718 VBPtrOffset = Src->getAggregateElement(I++);
2719 if (MSInheritanceAttr::hasVBTableOffsetField(SrcInheritance))
2720 VirtualBaseAdjustmentOffset = Src->getAggregateElement(I++);
2723 // For data pointers, we adjust the field offset directly. For functions, we
2724 // have a separate field.
2725 llvm::Constant *Adj = getMemberPointerAdjustment(E);
2727 Adj = llvm::ConstantExpr::getTruncOrBitCast(Adj, CGM.IntTy);
2728 llvm::Constant *&NVAdjustField =
2729 IsFunc ? NonVirtualBaseAdjustment : FirstField;
2730 bool IsDerivedToBase = (E->getCastKind() == CK_DerivedToBaseMemberPointer);
2731 if (!NVAdjustField) // If this field didn't exist in src, it's zero.
2732 NVAdjustField = getZeroInt();
2733 if (IsDerivedToBase)
2734 NVAdjustField = llvm::ConstantExpr::getNSWSub(NVAdjustField, Adj);
2736 NVAdjustField = llvm::ConstantExpr::getNSWAdd(NVAdjustField, Adj);
2739 // FIXME PR15713: Support conversions through virtually derived classes.
2741 // Recompose dst from the null struct and the adjusted fields from src.
2742 if (MSInheritanceAttr::hasOnlyOneField(IsFunc, DstInheritance))
2745 llvm::SmallVector<llvm::Constant *, 4> Fields;
2746 Fields.push_back(FirstField);
2747 if (MSInheritanceAttr::hasNVOffsetField(IsFunc, DstInheritance))
2748 Fields.push_back(getConstantOrZeroInt(NonVirtualBaseAdjustment));
2749 if (MSInheritanceAttr::hasVBPtrOffsetField(DstInheritance))
2750 Fields.push_back(getConstantOrZeroInt(VBPtrOffset));
2751 if (MSInheritanceAttr::hasVBTableOffsetField(DstInheritance))
2752 Fields.push_back(getConstantOrZeroInt(VirtualBaseAdjustmentOffset));
2753 return llvm::ConstantStruct::getAnon(Fields);
2756 llvm::Value *MicrosoftCXXABI::EmitLoadOfMemberFunctionPointer(
2757 CodeGenFunction &CGF, const Expr *E, llvm::Value *&This,
2758 llvm::Value *MemPtr, const MemberPointerType *MPT) {
2759 assert(MPT->isMemberFunctionPointer());
2760 const FunctionProtoType *FPT =
2761 MPT->getPointeeType()->castAs<FunctionProtoType>();
2762 const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
2763 llvm::FunctionType *FTy =
2764 CGM.getTypes().GetFunctionType(
2765 CGM.getTypes().arrangeCXXMethodType(RD, FPT));
2766 CGBuilderTy &Builder = CGF.Builder;
2768 MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel();
2770 // Extract the fields we need, regardless of model. We'll apply them if we
2772 llvm::Value *FunctionPointer = MemPtr;
2773 llvm::Value *NonVirtualBaseAdjustment = nullptr;
2774 llvm::Value *VirtualBaseAdjustmentOffset = nullptr;
2775 llvm::Value *VBPtrOffset = nullptr;
2776 if (MemPtr->getType()->isStructTy()) {
2777 // We need to extract values.
2779 FunctionPointer = Builder.CreateExtractValue(MemPtr, I++);
2780 if (MSInheritanceAttr::hasNVOffsetField(MPT, Inheritance))
2781 NonVirtualBaseAdjustment = Builder.CreateExtractValue(MemPtr, I++);
2782 if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance))
2783 VBPtrOffset = Builder.CreateExtractValue(MemPtr, I++);
2784 if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance))
2785 VirtualBaseAdjustmentOffset = Builder.CreateExtractValue(MemPtr, I++);
2788 if (VirtualBaseAdjustmentOffset) {
2789 This = AdjustVirtualBase(CGF, E, RD, This, VirtualBaseAdjustmentOffset,
2793 if (NonVirtualBaseAdjustment) {
2794 // Apply the adjustment and cast back to the original struct type.
2795 llvm::Value *Ptr = Builder.CreateBitCast(This, Builder.getInt8PtrTy());
2796 Ptr = Builder.CreateInBoundsGEP(Ptr, NonVirtualBaseAdjustment);
2797 This = Builder.CreateBitCast(Ptr, This->getType(), "this.adjusted");
2800 return Builder.CreateBitCast(FunctionPointer, FTy->getPointerTo());
2803 CGCXXABI *clang::CodeGen::CreateMicrosoftCXXABI(CodeGenModule &CGM) {
2804 return new MicrosoftCXXABI(CGM);
2807 // MS RTTI Overview:
2808 // The run time type information emitted by cl.exe contains 5 distinct types of
2809 // structures. Many of them reference each other.
2811 // TypeInfo: Static classes that are returned by typeid.
2813 // CompleteObjectLocator: Referenced by vftables. They contain information
2814 // required for dynamic casting, including OffsetFromTop. They also contain
2815 // a reference to the TypeInfo for the type and a reference to the
2816 // CompleteHierarchyDescriptor for the type.
2818 // ClassHieararchyDescriptor: Contains information about a class hierarchy.
2819 // Used during dynamic_cast to walk a class hierarchy. References a base
2820 // class array and the size of said array.
2822 // BaseClassArray: Contains a list of classes in a hierarchy. BaseClassArray is
2823 // somewhat of a misnomer because the most derived class is also in the list
2824 // as well as multiple copies of virtual bases (if they occur multiple times
2825 // in the hiearchy.) The BaseClassArray contains one BaseClassDescriptor for
2826 // every path in the hierarchy, in pre-order depth first order. Note, we do
2827 // not declare a specific llvm type for BaseClassArray, it's merely an array
2828 // of BaseClassDescriptor pointers.
2830 // BaseClassDescriptor: Contains information about a class in a class hierarchy.
2831 // BaseClassDescriptor is also somewhat of a misnomer for the same reason that
2832 // BaseClassArray is. It contains information about a class within a
2833 // hierarchy such as: is this base is ambiguous and what is its offset in the
2834 // vbtable. The names of the BaseClassDescriptors have all of their fields
2835 // mangled into them so they can be aggressively deduplicated by the linker.
2837 static llvm::GlobalVariable *getTypeInfoVTable(CodeGenModule &CGM) {
2838 StringRef MangledName("\01??_7type_info@@6B@");
2839 if (auto VTable = CGM.getModule().getNamedGlobal(MangledName))
2841 return new llvm::GlobalVariable(CGM.getModule(), CGM.Int8PtrTy,
2843 llvm::GlobalVariable::ExternalLinkage,
2844 /*Initializer=*/nullptr, MangledName);
2849 /// \brief A Helper struct that stores information about a class in a class
2850 /// hierarchy. The information stored in these structs struct is used during
2851 /// the generation of ClassHierarchyDescriptors and BaseClassDescriptors.
2852 // During RTTI creation, MSRTTIClasses are stored in a contiguous array with
2853 // implicit depth first pre-order tree connectivity. getFirstChild and
2854 // getNextSibling allow us to walk the tree efficiently.
2855 struct MSRTTIClass {
2857 IsPrivateOnPath = 1 | 8,
2861 HasHierarchyDescriptor = 64
2863 MSRTTIClass(const CXXRecordDecl *RD) : RD(RD) {}
2864 uint32_t initialize(const MSRTTIClass *Parent,
2865 const CXXBaseSpecifier *Specifier);
2867 MSRTTIClass *getFirstChild() { return this + 1; }
2868 static MSRTTIClass *getNextChild(MSRTTIClass *Child) {
2869 return Child + 1 + Child->NumBases;
2872 const CXXRecordDecl *RD, *VirtualRoot;
2873 uint32_t Flags, NumBases, OffsetInVBase;
2876 /// \brief Recursively initialize the base class array.
2877 uint32_t MSRTTIClass::initialize(const MSRTTIClass *Parent,
2878 const CXXBaseSpecifier *Specifier) {
2879 Flags = HasHierarchyDescriptor;
2881 VirtualRoot = nullptr;
2884 if (Specifier->getAccessSpecifier() != AS_public)
2885 Flags |= IsPrivate | IsPrivateOnPath;
2886 if (Specifier->isVirtual()) {
2891 if (Parent->Flags & IsPrivateOnPath)
2892 Flags |= IsPrivateOnPath;
2893 VirtualRoot = Parent->VirtualRoot;
2894 OffsetInVBase = Parent->OffsetInVBase + RD->getASTContext()
2895 .getASTRecordLayout(Parent->RD).getBaseClassOffset(RD).getQuantity();
2899 MSRTTIClass *Child = getFirstChild();
2900 for (const CXXBaseSpecifier &Base : RD->bases()) {
2901 NumBases += Child->initialize(this, &Base) + 1;
2902 Child = getNextChild(Child);
2907 static llvm::GlobalValue::LinkageTypes getLinkageForRTTI(QualType Ty) {
2908 switch (Ty->getLinkage()) {
2910 case InternalLinkage:
2911 case UniqueExternalLinkage:
2912 return llvm::GlobalValue::InternalLinkage;
2914 case VisibleNoLinkage:
2915 case ExternalLinkage:
2916 return llvm::GlobalValue::LinkOnceODRLinkage;
2918 llvm_unreachable("Invalid linkage!");
2921 /// \brief An ephemeral helper class for building MS RTTI types. It caches some
2922 /// calls to the module and information about the most derived class in a
2924 struct MSRTTIBuilder {
2926 HasBranchingHierarchy = 1,
2927 HasVirtualBranchingHierarchy = 2,
2928 HasAmbiguousBases = 4
2931 MSRTTIBuilder(MicrosoftCXXABI &ABI, const CXXRecordDecl *RD)
2932 : CGM(ABI.CGM), Context(CGM.getContext()),
2933 VMContext(CGM.getLLVMContext()), Module(CGM.getModule()), RD(RD),
2934 Linkage(getLinkageForRTTI(CGM.getContext().getTagDeclType(RD))),
2937 llvm::GlobalVariable *getBaseClassDescriptor(const MSRTTIClass &Classes);
2938 llvm::GlobalVariable *
2939 getBaseClassArray(SmallVectorImpl<MSRTTIClass> &Classes);
2940 llvm::GlobalVariable *getClassHierarchyDescriptor();
2941 llvm::GlobalVariable *getCompleteObjectLocator(const VPtrInfo *Info);
2944 ASTContext &Context;
2945 llvm::LLVMContext &VMContext;
2946 llvm::Module &Module;
2947 const CXXRecordDecl *RD;
2948 llvm::GlobalVariable::LinkageTypes Linkage;
2949 MicrosoftCXXABI &ABI;
2954 /// \brief Recursively serializes a class hierarchy in pre-order depth first
2956 static void serializeClassHierarchy(SmallVectorImpl<MSRTTIClass> &Classes,
2957 const CXXRecordDecl *RD) {
2958 Classes.push_back(MSRTTIClass(RD));
2959 for (const CXXBaseSpecifier &Base : RD->bases())
2960 serializeClassHierarchy(Classes, Base.getType()->getAsCXXRecordDecl());
2963 /// \brief Find ambiguity among base classes.
2965 detectAmbiguousBases(SmallVectorImpl<MSRTTIClass> &Classes) {
2966 llvm::SmallPtrSet<const CXXRecordDecl *, 8> VirtualBases;
2967 llvm::SmallPtrSet<const CXXRecordDecl *, 8> UniqueBases;
2968 llvm::SmallPtrSet<const CXXRecordDecl *, 8> AmbiguousBases;
2969 for (MSRTTIClass *Class = &Classes.front(); Class <= &Classes.back();) {
2970 if ((Class->Flags & MSRTTIClass::IsVirtual) &&
2971 !VirtualBases.insert(Class->RD).second) {
2972 Class = MSRTTIClass::getNextChild(Class);
2975 if (!UniqueBases.insert(Class->RD).second)
2976 AmbiguousBases.insert(Class->RD);
2979 if (AmbiguousBases.empty())
2981 for (MSRTTIClass &Class : Classes)
2982 if (AmbiguousBases.count(Class.RD))
2983 Class.Flags |= MSRTTIClass::IsAmbiguous;
2986 llvm::GlobalVariable *MSRTTIBuilder::getClassHierarchyDescriptor() {
2987 SmallString<256> MangledName;
2989 llvm::raw_svector_ostream Out(MangledName);
2990 ABI.getMangleContext().mangleCXXRTTIClassHierarchyDescriptor(RD, Out);
2993 // Check to see if we've already declared this ClassHierarchyDescriptor.
2994 if (auto CHD = Module.getNamedGlobal(MangledName))
2997 // Serialize the class hierarchy and initialize the CHD Fields.
2998 SmallVector<MSRTTIClass, 8> Classes;
2999 serializeClassHierarchy(Classes, RD);
3000 Classes.front().initialize(/*Parent=*/nullptr, /*Specifier=*/nullptr);
3001 detectAmbiguousBases(Classes);
3003 for (auto Class : Classes) {
3004 if (Class.RD->getNumBases() > 1)
3005 Flags |= HasBranchingHierarchy;
3006 // Note: cl.exe does not calculate "HasAmbiguousBases" correctly. We
3007 // believe the field isn't actually used.
3008 if (Class.Flags & MSRTTIClass::IsAmbiguous)
3009 Flags |= HasAmbiguousBases;
3011 if ((Flags & HasBranchingHierarchy) && RD->getNumVBases() != 0)
3012 Flags |= HasVirtualBranchingHierarchy;
3013 // These gep indices are used to get the address of the first element of the
3014 // base class array.
3015 llvm::Value *GEPIndices[] = {llvm::ConstantInt::get(CGM.IntTy, 0),
3016 llvm::ConstantInt::get(CGM.IntTy, 0)};
3018 // Forward-declare the class hierarchy descriptor
3019 auto Type = ABI.getClassHierarchyDescriptorType();
3020 auto CHD = new llvm::GlobalVariable(Module, Type, /*Constant=*/true, Linkage,
3021 /*Initializer=*/nullptr,
3022 StringRef(MangledName));
3023 if (CHD->isWeakForLinker())
3024 CHD->setComdat(CGM.getModule().getOrInsertComdat(CHD->getName()));
3026 auto *Bases = getBaseClassArray(Classes);
3028 // Initialize the base class ClassHierarchyDescriptor.
3029 llvm::Constant *Fields[] = {
3030 llvm::ConstantInt::get(CGM.IntTy, 0), // Unknown
3031 llvm::ConstantInt::get(CGM.IntTy, Flags),
3032 llvm::ConstantInt::get(CGM.IntTy, Classes.size()),
3033 ABI.getImageRelativeConstant(llvm::ConstantExpr::getInBoundsGetElementPtr(
3034 Bases->getValueType(), Bases,
3035 llvm::ArrayRef<llvm::Value *>(GEPIndices))),
3037 CHD->setInitializer(llvm::ConstantStruct::get(Type, Fields));
3041 llvm::GlobalVariable *
3042 MSRTTIBuilder::getBaseClassArray(SmallVectorImpl<MSRTTIClass> &Classes) {
3043 SmallString<256> MangledName;
3045 llvm::raw_svector_ostream Out(MangledName);
3046 ABI.getMangleContext().mangleCXXRTTIBaseClassArray(RD, Out);
3049 // Forward-declare the base class array.
3050 // cl.exe pads the base class array with 1 (in 32 bit mode) or 4 (in 64 bit
3051 // mode) bytes of padding. We provide a pointer sized amount of padding by
3052 // adding +1 to Classes.size(). The sections have pointer alignment and are
3053 // marked pick-any so it shouldn't matter.
3054 llvm::Type *PtrType = ABI.getImageRelativeType(
3055 ABI.getBaseClassDescriptorType()->getPointerTo());
3056 auto *ArrType = llvm::ArrayType::get(PtrType, Classes.size() + 1);
3058 new llvm::GlobalVariable(Module, ArrType,
3059 /*Constant=*/true, Linkage,
3060 /*Initializer=*/nullptr, StringRef(MangledName));
3061 if (BCA->isWeakForLinker())
3062 BCA->setComdat(CGM.getModule().getOrInsertComdat(BCA->getName()));
3064 // Initialize the BaseClassArray.
3065 SmallVector<llvm::Constant *, 8> BaseClassArrayData;
3066 for (MSRTTIClass &Class : Classes)
3067 BaseClassArrayData.push_back(
3068 ABI.getImageRelativeConstant(getBaseClassDescriptor(Class)));
3069 BaseClassArrayData.push_back(llvm::Constant::getNullValue(PtrType));
3070 BCA->setInitializer(llvm::ConstantArray::get(ArrType, BaseClassArrayData));
3074 llvm::GlobalVariable *
3075 MSRTTIBuilder::getBaseClassDescriptor(const MSRTTIClass &Class) {
3076 // Compute the fields for the BaseClassDescriptor. They are computed up front
3077 // because they are mangled into the name of the object.
3078 uint32_t OffsetInVBTable = 0;
3079 int32_t VBPtrOffset = -1;
3080 if (Class.VirtualRoot) {
3081 auto &VTableContext = CGM.getMicrosoftVTableContext();
3082 OffsetInVBTable = VTableContext.getVBTableIndex(RD, Class.VirtualRoot) * 4;
3083 VBPtrOffset = Context.getASTRecordLayout(RD).getVBPtrOffset().getQuantity();
3086 SmallString<256> MangledName;
3088 llvm::raw_svector_ostream Out(MangledName);
3089 ABI.getMangleContext().mangleCXXRTTIBaseClassDescriptor(
3090 Class.RD, Class.OffsetInVBase, VBPtrOffset, OffsetInVBTable,
3094 // Check to see if we've already declared this object.
3095 if (auto BCD = Module.getNamedGlobal(MangledName))
3098 // Forward-declare the base class descriptor.
3099 auto Type = ABI.getBaseClassDescriptorType();
3101 new llvm::GlobalVariable(Module, Type, /*Constant=*/true, Linkage,
3102 /*Initializer=*/nullptr, StringRef(MangledName));
3103 if (BCD->isWeakForLinker())
3104 BCD->setComdat(CGM.getModule().getOrInsertComdat(BCD->getName()));
3106 // Initialize the BaseClassDescriptor.
3107 llvm::Constant *Fields[] = {
3108 ABI.getImageRelativeConstant(
3109 ABI.getAddrOfRTTIDescriptor(Context.getTypeDeclType(Class.RD))),
3110 llvm::ConstantInt::get(CGM.IntTy, Class.NumBases),
3111 llvm::ConstantInt::get(CGM.IntTy, Class.OffsetInVBase),
3112 llvm::ConstantInt::get(CGM.IntTy, VBPtrOffset),
3113 llvm::ConstantInt::get(CGM.IntTy, OffsetInVBTable),
3114 llvm::ConstantInt::get(CGM.IntTy, Class.Flags),
3115 ABI.getImageRelativeConstant(
3116 MSRTTIBuilder(ABI, Class.RD).getClassHierarchyDescriptor()),
3118 BCD->setInitializer(llvm::ConstantStruct::get(Type, Fields));
3122 llvm::GlobalVariable *
3123 MSRTTIBuilder::getCompleteObjectLocator(const VPtrInfo *Info) {
3124 SmallString<256> MangledName;
3126 llvm::raw_svector_ostream Out(MangledName);
3127 ABI.getMangleContext().mangleCXXRTTICompleteObjectLocator(RD, Info->MangledPath, Out);
3130 // Check to see if we've already computed this complete object locator.
3131 if (auto COL = Module.getNamedGlobal(MangledName))
3134 // Compute the fields of the complete object locator.
3135 int OffsetToTop = Info->FullOffsetInMDC.getQuantity();
3136 int VFPtrOffset = 0;
3137 // The offset includes the vtordisp if one exists.
3138 if (const CXXRecordDecl *VBase = Info->getVBaseWithVPtr())
3139 if (Context.getASTRecordLayout(RD)
3140 .getVBaseOffsetsMap()
3142 ->second.hasVtorDisp())
3143 VFPtrOffset = Info->NonVirtualOffset.getQuantity() + 4;
3145 // Forward-declare the complete object locator.
3146 llvm::StructType *Type = ABI.getCompleteObjectLocatorType();
3147 auto COL = new llvm::GlobalVariable(Module, Type, /*Constant=*/true, Linkage,
3148 /*Initializer=*/nullptr, StringRef(MangledName));
3150 // Initialize the CompleteObjectLocator.
3151 llvm::Constant *Fields[] = {
3152 llvm::ConstantInt::get(CGM.IntTy, ABI.isImageRelative()),
3153 llvm::ConstantInt::get(CGM.IntTy, OffsetToTop),
3154 llvm::ConstantInt::get(CGM.IntTy, VFPtrOffset),
3155 ABI.getImageRelativeConstant(
3156 CGM.GetAddrOfRTTIDescriptor(Context.getTypeDeclType(RD))),
3157 ABI.getImageRelativeConstant(getClassHierarchyDescriptor()),
3158 ABI.getImageRelativeConstant(COL),
3160 llvm::ArrayRef<llvm::Constant *> FieldsRef(Fields);
3161 if (!ABI.isImageRelative())
3162 FieldsRef = FieldsRef.drop_back();
3163 COL->setInitializer(llvm::ConstantStruct::get(Type, FieldsRef));
3164 if (COL->isWeakForLinker())
3165 COL->setComdat(CGM.getModule().getOrInsertComdat(COL->getName()));
3169 static QualType decomposeTypeForEH(ASTContext &Context, QualType T,
3170 bool &IsConst, bool &IsVolatile) {
3171 T = Context.getExceptionObjectType(T);
3173 // C++14 [except.handle]p3:
3174 // A handler is a match for an exception object of type E if [...]
3175 // - the handler is of type cv T or const T& where T is a pointer type and
3176 // E is a pointer type that can be converted to T by [...]
3177 // - a qualification conversion
3180 QualType PointeeType = T->getPointeeType();
3181 if (!PointeeType.isNull()) {
3182 IsConst = PointeeType.isConstQualified();
3183 IsVolatile = PointeeType.isVolatileQualified();
3186 // Member pointer types like "const int A::*" are represented by having RTTI
3187 // for "int A::*" and separately storing the const qualifier.
3188 if (const auto *MPTy = T->getAs<MemberPointerType>())
3189 T = Context.getMemberPointerType(PointeeType.getUnqualifiedType(),
3192 // Pointer types like "const int * const *" are represented by having RTTI
3193 // for "const int **" and separately storing the const qualifier.
3194 if (T->isPointerType())
3195 T = Context.getPointerType(PointeeType.getUnqualifiedType());
3201 MicrosoftCXXABI::getAddrOfCXXCatchHandlerType(QualType Type,
3202 QualType CatchHandlerType) {
3203 // TypeDescriptors for exceptions never have qualified pointer types,
3204 // qualifiers are stored seperately in order to support qualification
3206 bool IsConst, IsVolatile;
3207 Type = decomposeTypeForEH(getContext(), Type, IsConst, IsVolatile);
3209 bool IsReference = CatchHandlerType->isReferenceType();
3219 SmallString<256> MangledName;
3221 llvm::raw_svector_ostream Out(MangledName);
3222 getMangleContext().mangleCXXCatchHandlerType(Type, Flags, Out);
3225 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(MangledName))
3226 return llvm::ConstantExpr::getBitCast(GV, CGM.Int8PtrTy);
3228 llvm::Constant *Fields[] = {
3229 llvm::ConstantInt::get(CGM.IntTy, Flags), // Flags
3230 getAddrOfRTTIDescriptor(Type), // TypeDescriptor
3232 llvm::StructType *CatchHandlerTypeType = getCatchHandlerTypeType();
3233 auto *Var = new llvm::GlobalVariable(
3234 CGM.getModule(), CatchHandlerTypeType, /*Constant=*/true,
3235 llvm::GlobalValue::PrivateLinkage,
3236 llvm::ConstantStruct::get(CatchHandlerTypeType, Fields),
3237 StringRef(MangledName));
3238 Var->setUnnamedAddr(true);
3239 Var->setSection("llvm.metadata");
3243 /// \brief Gets a TypeDescriptor. Returns a llvm::Constant * rather than a
3244 /// llvm::GlobalVariable * because different type descriptors have different
3245 /// types, and need to be abstracted. They are abstracting by casting the
3246 /// address to an Int8PtrTy.
3247 llvm::Constant *MicrosoftCXXABI::getAddrOfRTTIDescriptor(QualType Type) {
3248 SmallString<256> MangledName;
3250 llvm::raw_svector_ostream Out(MangledName);
3251 getMangleContext().mangleCXXRTTI(Type, Out);
3254 // Check to see if we've already declared this TypeDescriptor.
3255 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(MangledName))
3256 return llvm::ConstantExpr::getBitCast(GV, CGM.Int8PtrTy);
3258 // Compute the fields for the TypeDescriptor.
3259 SmallString<256> TypeInfoString;
3261 llvm::raw_svector_ostream Out(TypeInfoString);
3262 getMangleContext().mangleCXXRTTIName(Type, Out);
3265 // Declare and initialize the TypeDescriptor.
3266 llvm::Constant *Fields[] = {
3267 getTypeInfoVTable(CGM), // VFPtr
3268 llvm::ConstantPointerNull::get(CGM.Int8PtrTy), // Runtime data
3269 llvm::ConstantDataArray::getString(CGM.getLLVMContext(), TypeInfoString)};
3270 llvm::StructType *TypeDescriptorType =
3271 getTypeDescriptorType(TypeInfoString);
3272 auto *Var = new llvm::GlobalVariable(
3273 CGM.getModule(), TypeDescriptorType, /*Constant=*/false,
3274 getLinkageForRTTI(Type),
3275 llvm::ConstantStruct::get(TypeDescriptorType, Fields),
3276 StringRef(MangledName));
3277 if (Var->isWeakForLinker())
3278 Var->setComdat(CGM.getModule().getOrInsertComdat(Var->getName()));
3279 return llvm::ConstantExpr::getBitCast(Var, CGM.Int8PtrTy);
3282 /// \brief Gets or a creates a Microsoft CompleteObjectLocator.
3283 llvm::GlobalVariable *
3284 MicrosoftCXXABI::getMSCompleteObjectLocator(const CXXRecordDecl *RD,
3285 const VPtrInfo *Info) {
3286 return MSRTTIBuilder(*this, RD).getCompleteObjectLocator(Info);
3289 static void emitCXXConstructor(CodeGenModule &CGM,
3290 const CXXConstructorDecl *ctor,
3291 StructorType ctorType) {
3292 // There are no constructor variants, always emit the complete destructor.
3293 llvm::Function *Fn = CGM.codegenCXXStructor(ctor, StructorType::Complete);
3294 CGM.maybeSetTrivialComdat(*ctor, *Fn);
3297 static void emitCXXDestructor(CodeGenModule &CGM, const CXXDestructorDecl *dtor,
3298 StructorType dtorType) {
3299 // The complete destructor is equivalent to the base destructor for
3300 // classes with no virtual bases, so try to emit it as an alias.
3301 if (!dtor->getParent()->getNumVBases() &&
3302 (dtorType == StructorType::Complete || dtorType == StructorType::Base)) {
3303 bool ProducedAlias = !CGM.TryEmitDefinitionAsAlias(
3304 GlobalDecl(dtor, Dtor_Complete), GlobalDecl(dtor, Dtor_Base), true);
3305 if (ProducedAlias) {
3306 if (dtorType == StructorType::Complete)
3308 if (dtor->isVirtual())
3309 CGM.getVTables().EmitThunks(GlobalDecl(dtor, Dtor_Complete));
3313 // The base destructor is equivalent to the base destructor of its
3314 // base class if there is exactly one non-virtual base class with a
3315 // non-trivial destructor, there are no fields with a non-trivial
3316 // destructor, and the body of the destructor is trivial.
3317 if (dtorType == StructorType::Base && !CGM.TryEmitBaseDestructorAsAlias(dtor))
3320 llvm::Function *Fn = CGM.codegenCXXStructor(dtor, dtorType);
3321 if (Fn->isWeakForLinker())
3322 Fn->setComdat(CGM.getModule().getOrInsertComdat(Fn->getName()));
3325 void MicrosoftCXXABI::emitCXXStructor(const CXXMethodDecl *MD,
3326 StructorType Type) {
3327 if (auto *CD = dyn_cast<CXXConstructorDecl>(MD)) {
3328 emitCXXConstructor(CGM, CD, Type);
3331 emitCXXDestructor(CGM, cast<CXXDestructorDecl>(MD), Type);
3335 MicrosoftCXXABI::getAddrOfCXXCtorClosure(const CXXConstructorDecl *CD,
3337 assert(CT == Ctor_CopyingClosure || CT == Ctor_DefaultClosure);
3339 // Calculate the mangled name.
3340 SmallString<256> ThunkName;
3341 llvm::raw_svector_ostream Out(ThunkName);
3342 getMangleContext().mangleCXXCtor(CD, CT, Out);
3345 // If the thunk has been generated previously, just return it.
3346 if (llvm::GlobalValue *GV = CGM.getModule().getNamedValue(ThunkName))
3347 return cast<llvm::Function>(GV);
3349 // Create the llvm::Function.
3350 const CGFunctionInfo &FnInfo = CGM.getTypes().arrangeMSCtorClosure(CD, CT);
3351 llvm::FunctionType *ThunkTy = CGM.getTypes().GetFunctionType(FnInfo);
3352 const CXXRecordDecl *RD = CD->getParent();
3353 QualType RecordTy = getContext().getRecordType(RD);
3354 llvm::Function *ThunkFn = llvm::Function::Create(
3355 ThunkTy, getLinkageForRTTI(RecordTy), ThunkName.str(), &CGM.getModule());
3356 ThunkFn->setCallingConv(static_cast<llvm::CallingConv::ID>(
3357 FnInfo.getEffectiveCallingConvention()));
3358 bool IsCopy = CT == Ctor_CopyingClosure;
3361 CodeGenFunction CGF(CGM);
3362 CGF.CurGD = GlobalDecl(CD, Ctor_Complete);
3364 // Build FunctionArgs.
3365 FunctionArgList FunctionArgs;
3367 // A constructor always starts with a 'this' pointer as its first argument.
3368 buildThisParam(CGF, FunctionArgs);
3370 // Following the 'this' pointer is a reference to the source object that we
3371 // are copying from.
3372 ImplicitParamDecl SrcParam(
3373 getContext(), nullptr, SourceLocation(), &getContext().Idents.get("src"),
3374 getContext().getLValueReferenceType(RecordTy,
3375 /*SpelledAsLValue=*/true));
3377 FunctionArgs.push_back(&SrcParam);
3379 // Constructors for classes which utilize virtual bases have an additional
3380 // parameter which indicates whether or not it is being delegated to by a more
3381 // derived constructor.
3382 ImplicitParamDecl IsMostDerived(getContext(), nullptr, SourceLocation(),
3383 &getContext().Idents.get("is_most_derived"),
3384 getContext().IntTy);
3385 // Only add the parameter to the list if thie class has virtual bases.
3386 if (RD->getNumVBases() > 0)
3387 FunctionArgs.push_back(&IsMostDerived);
3389 // Start defining the function.
3390 CGF.StartFunction(GlobalDecl(), FnInfo.getReturnType(), ThunkFn, FnInfo,
3391 FunctionArgs, CD->getLocation(), SourceLocation());
3393 llvm::Value *This = getThisValue(CGF);
3395 llvm::Value *SrcVal =
3396 IsCopy ? CGF.Builder.CreateLoad(CGF.GetAddrOfLocalVar(&SrcParam), "src")
3401 // Push the this ptr.
3402 Args.add(RValue::get(This), CD->getThisType(getContext()));
3404 // Push the src ptr.
3406 Args.add(RValue::get(SrcVal), SrcParam.getType());
3408 // Add the rest of the default arguments.
3409 std::vector<Stmt *> ArgVec;
3410 for (unsigned I = IsCopy ? 1 : 0, E = CD->getNumParams(); I != E; ++I) {
3411 Stmt *DefaultArg = getContext().getDefaultArgExprForConstructor(CD, I);
3412 assert(DefaultArg && "sema forgot to instantiate default args");
3413 ArgVec.push_back(DefaultArg);
3416 CodeGenFunction::RunCleanupsScope Cleanups(CGF);
3418 const auto *FPT = CD->getType()->castAs<FunctionProtoType>();
3419 ConstExprIterator ArgBegin(ArgVec.data()),
3420 ArgEnd(ArgVec.data() + ArgVec.size());
3421 CGF.EmitCallArgs(Args, FPT, ArgBegin, ArgEnd, CD, IsCopy ? 1 : 0);
3423 // Insert any ABI-specific implicit constructor arguments.
3424 unsigned ExtraArgs = addImplicitConstructorArgs(CGF, CD, Ctor_Complete,
3425 /*ForVirtualBase=*/false,
3426 /*Delegating=*/false, Args);
3428 // Call the destructor with our arguments.
3429 llvm::Value *CalleeFn = CGM.getAddrOfCXXStructor(CD, StructorType::Complete);
3430 const CGFunctionInfo &CalleeInfo = CGM.getTypes().arrangeCXXConstructorCall(
3431 Args, CD, Ctor_Complete, ExtraArgs);
3432 CGF.EmitCall(CalleeInfo, CalleeFn, ReturnValueSlot(), Args, CD);
3434 Cleanups.ForceCleanup();
3436 // Emit the ret instruction, remove any temporary instructions created for the
3438 CGF.FinishFunction(SourceLocation());
3443 llvm::Constant *MicrosoftCXXABI::getCatchableType(QualType T,
3445 int32_t VBPtrOffset,
3447 assert(!T->isReferenceType());
3449 CXXRecordDecl *RD = T->getAsCXXRecordDecl();
3450 const CXXConstructorDecl *CD =
3451 RD ? CGM.getContext().getCopyConstructorForExceptionObject(RD) : nullptr;
3452 CXXCtorType CT = Ctor_Complete;
3454 if (!hasDefaultCXXMethodCC(getContext(), CD) || CD->getNumParams() != 1)
3455 CT = Ctor_CopyingClosure;
3457 uint32_t Size = getContext().getTypeSizeInChars(T).getQuantity();
3458 SmallString<256> MangledName;
3460 llvm::raw_svector_ostream Out(MangledName);
3461 getMangleContext().mangleCXXCatchableType(T, CD, CT, Size, NVOffset,
3462 VBPtrOffset, VBIndex, Out);
3464 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(MangledName))
3465 return getImageRelativeConstant(GV);
3467 // The TypeDescriptor is used by the runtime to determine if a catch handler
3468 // is appropriate for the exception object.
3469 llvm::Constant *TD = getImageRelativeConstant(getAddrOfRTTIDescriptor(T));
3471 // The runtime is responsible for calling the copy constructor if the
3472 // exception is caught by value.
3473 llvm::Constant *CopyCtor;
3475 if (CT == Ctor_CopyingClosure)
3476 CopyCtor = getAddrOfCXXCtorClosure(CD, Ctor_CopyingClosure);
3478 CopyCtor = CGM.getAddrOfCXXStructor(CD, StructorType::Complete);
3480 CopyCtor = llvm::ConstantExpr::getBitCast(CopyCtor, CGM.Int8PtrTy);
3482 CopyCtor = llvm::Constant::getNullValue(CGM.Int8PtrTy);
3484 CopyCtor = getImageRelativeConstant(CopyCtor);
3486 bool IsScalar = !RD;
3487 bool HasVirtualBases = false;
3488 bool IsStdBadAlloc = false; // std::bad_alloc is special for some reason.
3489 QualType PointeeType = T;
3490 if (T->isPointerType())
3491 PointeeType = T->getPointeeType();
3492 if (const CXXRecordDecl *RD = PointeeType->getAsCXXRecordDecl()) {
3493 HasVirtualBases = RD->getNumVBases() > 0;
3494 if (IdentifierInfo *II = RD->getIdentifier())
3495 IsStdBadAlloc = II->isStr("bad_alloc") && RD->isInStdNamespace();
3498 // Encode the relevant CatchableType properties into the Flags bitfield.
3499 // FIXME: Figure out how bits 2 or 8 can get set.
3503 if (HasVirtualBases)
3508 llvm::Constant *Fields[] = {
3509 llvm::ConstantInt::get(CGM.IntTy, Flags), // Flags
3510 TD, // TypeDescriptor
3511 llvm::ConstantInt::get(CGM.IntTy, NVOffset), // NonVirtualAdjustment
3512 llvm::ConstantInt::get(CGM.IntTy, VBPtrOffset), // OffsetToVBPtr
3513 llvm::ConstantInt::get(CGM.IntTy, VBIndex), // VBTableIndex
3514 llvm::ConstantInt::get(CGM.IntTy, Size), // Size
3515 CopyCtor // CopyCtor
3517 llvm::StructType *CTType = getCatchableTypeType();
3518 auto *GV = new llvm::GlobalVariable(
3519 CGM.getModule(), CTType, /*Constant=*/true, getLinkageForRTTI(T),
3520 llvm::ConstantStruct::get(CTType, Fields), StringRef(MangledName));
3521 GV->setUnnamedAddr(true);
3522 GV->setSection(".xdata");
3523 if (GV->isWeakForLinker())
3524 GV->setComdat(CGM.getModule().getOrInsertComdat(GV->getName()));
3525 return getImageRelativeConstant(GV);
3528 llvm::GlobalVariable *MicrosoftCXXABI::getCatchableTypeArray(QualType T) {
3529 assert(!T->isReferenceType());
3531 // See if we've already generated a CatchableTypeArray for this type before.
3532 llvm::GlobalVariable *&CTA = CatchableTypeArrays[T];
3536 // Ensure that we don't have duplicate entries in our CatchableTypeArray by
3537 // using a SmallSetVector. Duplicates may arise due to virtual bases
3538 // occurring more than once in the hierarchy.
3539 llvm::SmallSetVector<llvm::Constant *, 2> CatchableTypes;
3541 // C++14 [except.handle]p3:
3542 // A handler is a match for an exception object of type E if [...]
3543 // - the handler is of type cv T or cv T& and T is an unambiguous public
3544 // base class of E, or
3545 // - the handler is of type cv T or const T& where T is a pointer type and
3546 // E is a pointer type that can be converted to T by [...]
3547 // - a standard pointer conversion (4.10) not involving conversions to
3548 // pointers to private or protected or ambiguous classes
3549 const CXXRecordDecl *MostDerivedClass = nullptr;
3550 bool IsPointer = T->isPointerType();
3552 MostDerivedClass = T->getPointeeType()->getAsCXXRecordDecl();
3554 MostDerivedClass = T->getAsCXXRecordDecl();
3556 // Collect all the unambiguous public bases of the MostDerivedClass.
3557 if (MostDerivedClass) {
3558 const ASTContext &Context = getContext();
3559 const ASTRecordLayout &MostDerivedLayout =
3560 Context.getASTRecordLayout(MostDerivedClass);
3561 MicrosoftVTableContext &VTableContext = CGM.getMicrosoftVTableContext();
3562 SmallVector<MSRTTIClass, 8> Classes;
3563 serializeClassHierarchy(Classes, MostDerivedClass);
3564 Classes.front().initialize(/*Parent=*/nullptr, /*Specifier=*/nullptr);
3565 detectAmbiguousBases(Classes);
3566 for (const MSRTTIClass &Class : Classes) {
3567 // Skip any ambiguous or private bases.
3569 (MSRTTIClass::IsPrivateOnPath | MSRTTIClass::IsAmbiguous))
3571 // Write down how to convert from a derived pointer to a base pointer.
3572 uint32_t OffsetInVBTable = 0;
3573 int32_t VBPtrOffset = -1;
3574 if (Class.VirtualRoot) {
3576 VTableContext.getVBTableIndex(MostDerivedClass, Class.VirtualRoot)*4;
3577 VBPtrOffset = MostDerivedLayout.getVBPtrOffset().getQuantity();
3580 // Turn our record back into a pointer if the exception object is a
3582 QualType RTTITy = QualType(Class.RD->getTypeForDecl(), 0);
3584 RTTITy = Context.getPointerType(RTTITy);
3585 CatchableTypes.insert(getCatchableType(RTTITy, Class.OffsetInVBase,
3586 VBPtrOffset, OffsetInVBTable));
3590 // C++14 [except.handle]p3:
3591 // A handler is a match for an exception object of type E if
3592 // - The handler is of type cv T or cv T& and E and T are the same type
3593 // (ignoring the top-level cv-qualifiers)
3594 CatchableTypes.insert(getCatchableType(T));
3596 // C++14 [except.handle]p3:
3597 // A handler is a match for an exception object of type E if
3598 // - the handler is of type cv T or const T& where T is a pointer type and
3599 // E is a pointer type that can be converted to T by [...]
3600 // - a standard pointer conversion (4.10) not involving conversions to
3601 // pointers to private or protected or ambiguous classes
3603 // C++14 [conv.ptr]p2:
3604 // A prvalue of type "pointer to cv T," where T is an object type, can be
3605 // converted to a prvalue of type "pointer to cv void".
3606 if (IsPointer && T->getPointeeType()->isObjectType())
3607 CatchableTypes.insert(getCatchableType(getContext().VoidPtrTy));
3609 // C++14 [except.handle]p3:
3610 // A handler is a match for an exception object of type E if [...]
3611 // - the handler is of type cv T or const T& where T is a pointer or
3612 // pointer to member type and E is std::nullptr_t.
3614 // We cannot possibly list all possible pointer types here, making this
3615 // implementation incompatible with the standard. However, MSVC includes an
3616 // entry for pointer-to-void in this case. Let's do the same.
3617 if (T->isNullPtrType())
3618 CatchableTypes.insert(getCatchableType(getContext().VoidPtrTy));
3620 uint32_t NumEntries = CatchableTypes.size();
3621 llvm::Type *CTType =
3622 getImageRelativeType(getCatchableTypeType()->getPointerTo());
3623 llvm::ArrayType *AT = llvm::ArrayType::get(CTType, NumEntries);
3624 llvm::StructType *CTAType = getCatchableTypeArrayType(NumEntries);
3625 llvm::Constant *Fields[] = {
3626 llvm::ConstantInt::get(CGM.IntTy, NumEntries), // NumEntries
3627 llvm::ConstantArray::get(
3628 AT, llvm::makeArrayRef(CatchableTypes.begin(),
3629 CatchableTypes.end())) // CatchableTypes
3631 SmallString<256> MangledName;
3633 llvm::raw_svector_ostream Out(MangledName);
3634 getMangleContext().mangleCXXCatchableTypeArray(T, NumEntries, Out);
3636 CTA = new llvm::GlobalVariable(
3637 CGM.getModule(), CTAType, /*Constant=*/true, getLinkageForRTTI(T),
3638 llvm::ConstantStruct::get(CTAType, Fields), StringRef(MangledName));
3639 CTA->setUnnamedAddr(true);
3640 CTA->setSection(".xdata");
3641 if (CTA->isWeakForLinker())
3642 CTA->setComdat(CGM.getModule().getOrInsertComdat(CTA->getName()));
3646 llvm::GlobalVariable *MicrosoftCXXABI::getThrowInfo(QualType T) {
3647 bool IsConst, IsVolatile;
3648 T = decomposeTypeForEH(getContext(), T, IsConst, IsVolatile);
3650 // The CatchableTypeArray enumerates the various (CV-unqualified) types that
3651 // the exception object may be caught as.
3652 llvm::GlobalVariable *CTA = getCatchableTypeArray(T);
3653 // The first field in a CatchableTypeArray is the number of CatchableTypes.
3654 // This is used as a component of the mangled name which means that we need to
3655 // know what it is in order to see if we have previously generated the
3657 uint32_t NumEntries =
3658 cast<llvm::ConstantInt>(CTA->getInitializer()->getAggregateElement(0U))
3659 ->getLimitedValue();
3661 SmallString<256> MangledName;
3663 llvm::raw_svector_ostream Out(MangledName);
3664 getMangleContext().mangleCXXThrowInfo(T, IsConst, IsVolatile, NumEntries,
3668 // Reuse a previously generated ThrowInfo if we have generated an appropriate
3670 if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(MangledName))
3673 // The RTTI TypeDescriptor uses an unqualified type but catch clauses must
3674 // be at least as CV qualified. Encode this requirement into the Flags
3682 // The cleanup-function (a destructor) must be called when the exception
3683 // object's lifetime ends.
3684 llvm::Constant *CleanupFn = llvm::Constant::getNullValue(CGM.Int8PtrTy);
3685 if (const CXXRecordDecl *RD = T->getAsCXXRecordDecl())
3686 if (CXXDestructorDecl *DtorD = RD->getDestructor())
3687 if (!DtorD->isTrivial())
3688 CleanupFn = llvm::ConstantExpr::getBitCast(
3689 CGM.getAddrOfCXXStructor(DtorD, StructorType::Complete),
3691 // This is unused as far as we can tell, initialize it to null.
3692 llvm::Constant *ForwardCompat =
3693 getImageRelativeConstant(llvm::Constant::getNullValue(CGM.Int8PtrTy));
3694 llvm::Constant *PointerToCatchableTypes = getImageRelativeConstant(
3695 llvm::ConstantExpr::getBitCast(CTA, CGM.Int8PtrTy));
3696 llvm::StructType *TIType = getThrowInfoType();
3697 llvm::Constant *Fields[] = {
3698 llvm::ConstantInt::get(CGM.IntTy, Flags), // Flags
3699 getImageRelativeConstant(CleanupFn), // CleanupFn
3700 ForwardCompat, // ForwardCompat
3701 PointerToCatchableTypes // CatchableTypeArray
3703 auto *GV = new llvm::GlobalVariable(
3704 CGM.getModule(), TIType, /*Constant=*/true, getLinkageForRTTI(T),
3705 llvm::ConstantStruct::get(TIType, Fields), StringRef(MangledName));
3706 GV->setUnnamedAddr(true);
3707 GV->setSection(".xdata");
3708 if (GV->isWeakForLinker())
3709 GV->setComdat(CGM.getModule().getOrInsertComdat(GV->getName()));
3713 void MicrosoftCXXABI::emitThrow(CodeGenFunction &CGF, const CXXThrowExpr *E) {
3714 const Expr *SubExpr = E->getSubExpr();
3715 QualType ThrowType = SubExpr->getType();
3716 // The exception object lives on the stack and it's address is passed to the
3717 // runtime function.
3718 llvm::AllocaInst *AI = CGF.CreateMemTemp(ThrowType);
3719 CGF.EmitAnyExprToMem(SubExpr, AI, ThrowType.getQualifiers(),
3722 // The so-called ThrowInfo is used to describe how the exception object may be
3724 llvm::GlobalVariable *TI = getThrowInfo(ThrowType);
3726 // Call into the runtime to throw the exception.
3727 llvm::Value *Args[] = {CGF.Builder.CreateBitCast(AI, CGM.Int8PtrTy), TI};
3728 CGF.EmitNoreturnRuntimeCallOrInvoke(getThrowFn(), Args);